Hi Jedte...., I have BT internet via Smart Hub 2 plus 2 extra discs and it is rock solid stable. I haven't needed to reboot my router once in the over 2 years I've had it, and consequently the IP address assigned to my B2 hasn't changed in all that time, so my 'bookmark' stays current.
I have 6 x SONOS one SLs with no other kit to connect them and it works brilliantly. I stay well clear of NAS, and I don't bother with setting up zones/groups of the SONOS speakers on the B2, I just leave them as individuals, which can all be playing from different Brennan output if I ever want them too . To send the same synchronised output to more than one of them I use the SONOS app to add speakers to or remove them from a groups 'in flight'.
The only thing you need to get used to is that SONOS builds queues to each speaker depending on what you've sent to it. So for example if you have Speakers A and B currently playing synced output and Speaker C playing something different, if you want to add C to the 'group' A/B so it plays the same synced music you need to clear down what is currently in the queue to C. Sounds complicated but brilliantly simple in the SONOS app.