Not sure I understand the question.

I think what you’re asking is if you can connect two Amps ( a CONNECT:AMP and a newer Sonos Amp) at the same time to a Sonos soundbar, and that answer is no. The maximum amount of devices in a Sonos ‘home theater’ room is 5.2, which is the soundbar (3 of those speaker channels) plus the surrounds (2 of those channels, the CONNECT:AMP or the Sonos Amp, but not both) and up to two subs (one of which must be a Gen 3 sub).

There is not a way to add more devices to that home theater room. You can, however, ‘group’ more devices, and when streaming music, they will all play in sync. It’s only when playing an input from the TV that you’ll get a slight delay between the home theater setup and the grouped rooms.

To be super clear, there is no way to use a Sonos soundbar as a ‘center’ channel device, and add any other Sonos device as the front right and front left speakers. 

If you’ve really replaced the Connect Amp by an Amp, and so the Connect Amp is no longer there, you should be able to add the Amp for surround. Since the Connect Amp had to be cable connected for surround and the Amp does not have to be: is wifi on the soundbar on?