The Port cannot control your receiver.  It can do limited control of some Onkyo and Pioneer units, like switching to the Sonos input when you start playing Sonos and controlling volume from the Sonos app, but no other abilities.  As far as Alexa control of your TV, that would require a Sonos Arc/Beam, or some other Alexa capable control device (Harmony remote, Fire TV Cube, etc). 

taberrebel21,
A lot to cover from the things mentioned in your post, but here’s a short summary...

By connecting the Port (Line) IN/OUT you will be able to receive stereo audio only from your existing 3rd party receiver and pass that to your other Sonos products and vice versa for music audio, but when sending TV audio from zone 2 (Playbar —> Port) it will not play in sync with the Port in zone1 - but that will likely not matter as each are in different rooms. 
 

You won’t be able to have full control of the 3rd party receiver/TV in zone 1 using either the Port or  the remote currently in use with the Sonos system in zone 2, nor will you be able to do that with Alexa (without additional hardware - see below*) - you will likely have to use the remotes as you already do at the moment.  

*Additional Hardware:

One device that maybe able to control all/most of your 3rd party devices in zone 1 (and zone 2), using Amazon Alexa, is the Logitech Harmony Hub, or their smart remotes. So you may want to do a bit more research around those. I will add I use the Logitech products and if you have not used them before, it’s a bit of a steep learning curve to set those up to control all your devices, but you may find that they are able to switch on/off your products, switch inputs, adjust/mute volume and change/pause TV channels, launch Device Apps etc; all using voice control (plus some other things too).

A firetv stick isn’t going to do anything for you.  The firetv cube is useful for a single room setup, but isn’t designed to work with multiple rooms...although you could get one for each room.  I’m not sure it will work for your particular setup since you’re trying to use the same video sources (consoles, blueray player, etc) in multiple rooms.

Harmony is probably the better option as it’s built to control up to 15 different devices (I believe that’s the limit). The catch for you is that your devices need to be controlled through a network connection to the device (which works for Sonos and several other devices) or an IR connection, same as the device remote.  IR is not an issue for devices located next to each other, but if they are in different rooms, you’ll need a wired IR blaster between the rooms   YOu’ll have to figure out whether that works for you or not.

And as pointed out, Harmony takes some time and training to get up to speed.  Once set though, your more complicate common tasks (turn on console, turn on receiver, swithc input, turn on TV, set volume...) can be done at the push of a button.

@Ken_Griffiths 

So if I went the harmony hub option(which is what I’m leaning towards) what app on my iPhone will I run it all through? (I know I will still want to use sonos for music most likely) and do I wire the hub to my receiver via hdmi?

I would go with the harmony elite, so you get the hub and a remote.  I end up using the remote 95% of the time, but you can use the harmony app for setup and as a remote.  If you integrate with Alexa, then you can run certain activites by voice, as I understand it.  I honestly haven’t messed much with this since I find the remote so easy to use.  For Sonos, I use either the Sonos app for Alexa voice control.

The harmony hub won’t actually be physically connected to your devices.  It will either connect to devices through your home network for control, or by IR.  Essentially, IR is what your existing TV and receiver remotes are using to control your TV and receiver respectively.  Harmony essentially just copies these features and puts them on a single remote and interface to control. It does more than that though since it lets you combine common activities into a single button press and other things to make control a bit easier.

1. So with the harmony elite(remote), I will be able to control nearly every function on the receiver, control volume on sonos devices, and turn tv’s on + off. Will also be able to create certain routines. “For example: turn on tv, will turn on receiver, will turn on dvd player”
2. voice control will be used for “simpler tasks”.
3. Where should I put the hub? As I’m going to need 2 IR blasters, one upstairs and the other downstairs. Will I need a splitter? or will it have 2 ports. I don't want to place it by either TV. Meaning I will need 2 IR blasters. How should I go about doing that?

The recommendations by @melvimbe (Danny) are what I would suggest too… and use the Logitech remote, hub and their myHarmony App. I’ve attached a couple of screenshots from my own App - just to give you a glance at the features. You may find tutorials online at places like YouTube etc.

Yes.  If your devices take IR remotes, than you can do anything with harmony that you could do with your device remote...and then set them up in what Harmony calls ‘activities’.

The activities are relatively smart too.  For example, I have one activity that turns on my TV, turns on my Nvidia Shield, and switches HDMI input. Turning that activity off knows to turn off the Shield and TV.  I have a 2nd activity that turns on TV, turns on xbox, and switches HDMI input.  If run the Shield activity, it runs as expected.  If I then turn on the xbox activity, it will turn skip turning on the TV since it’s already on, turn on xbox, and switch inputs. (it may turn on shield too, not sure)

My understanding is that you would be able to run your activities, so that could be rather complex tasks. 

They hub itself is an IR ‘sender’ so it will control device near by it.  There are two ports for IR blasters  and it comes with two cables which are about 6 feet long each.  I actually have my hub in a closet behind my TV, and the cables were not long enough to get there, so I got this 6 ft extension.

https://www.amazon.com/gp/product/B075SSKCDY/

No issues for me, but you may need longer cables.  Be careful though as there are different types of cables, so make sure you get one that is mono, not stereo, and is 2.5mm barrel.  You can also get adapters between barrel sizes if you need to.

@melvimbe 

What if I just connect my receiver to an ip control(cat5?)

can I connect that to my network of “controllable devices” via harmony? or even without a hub?

Firstly, you cannot create activities in the Harmony App without a Logitech remote, or hub ..and control over a wireless connection may depend on how the receiver works currently - some manufacturers and developers have added devices (and default ‘activities’) to the Logitech database for downloading to their devices through the Harmony App. The database of device compatibility  can be searched here:

https://support.myharmony.com/en-us/compatibility

But IP control on the Receiver depends on what the manufacturer has built into their device.

I have an anthem mrx520, your link says it is a supported device, but does not give information whether I can use ip control, or if I have to use ir control. we have already established I can use the ir control with the harmony hub. But now that I'm looking at it, it may be more beneficial, easier to use ip control. I would still get a harmony hub(I would still have to, but instead of connecting the remote through ir(I would have to wire a blaster through walls)), it would connect through wifi. Am I mistaken? Or is this a possibility?

I may also have to add a smartthings hub? or this completely irrelevant?

Is there an App from the manufacturer to control the Receiver over WiFi already? - if not, then it might (likely) be infrared control only. You would need to speak with the manufacturers support desk to get a definitive answer. 

Yes, it connects via ethernet, not wirelessly to the network. I have a anthem remote app on my phone that connects to it. It would seem that this should be supported with harmony.

It might be. You could check on a Harmony support forum. They connect to thousands (I think) of discrete devices.