Hi @deep80
Welcome to the Sonos Community!
There’s no mention of the Huawei 628 in our Incompatible Network Hardware list, but that router is an LTE router (meaning it connects to mobile/cellular networks) which we do not support. That doesn’t mean it won’t work, however - just that our technical support team will not troubleshoot such a system. There’s a distinct possibility that it won’t work, though (which may depend on either the router or the brand of SIM card fitted).
A stereo pair of Roams will need a WiFi network to remain a stereo pair - if there’s no WiFi, you may be able to Bluetooth to both speakers at the same time (if the host device specifically supports doing that), but playback would unlikely to be in true stereo - more likely, dual mono.
You shouldn’t have any trouble Bluetooth-ing to a stereo pair of Roams on your home broadband WiFi.
If you buy direct from our store, you will have 100 days to decide and test - if you’re not happy, return the units for a full refund. We will cover all shipping costs.
I hope this helps.