Topspin14m

Yup, though to clarify, this isn't needed in Control4 as such as you're linking to each r3espective account as you initiate to spotify connect setting, so as long as the phones are on different accounts, there's no need to have specific drivers for each phone.

What do you mean by sharing "one account" on Spotify?  If you don't have a Spotify Family plan (and it is just a Spotify plan), you can only play one song at once.  Spotify is normally ~$9.99 a month.  The family plan is $15 a month.  With the family plan, you can have separate accounts and separate streams playing, but I am pretty sure you still cannot play two songs on one account, so this sounds like an account issue to me.  For instance, on Sonos you would have to set up "my Spotify" and "wife's Spotify" [using real names obviously] and tell Sonos which account to play the song on.
Try this:  Play a song on your phone.  Then have another family member play a song on their phone.  Do both play or does the music on your phone stop?  If both continue to play, are both phones logged in under separate Spotify logins or the same one?

you can't browse sonos music via c4 interface, you have to browse via sonos.  You get meta data and transport controls and you can only start a playlist or favorite via c4 interface 
Note: these apply to all Sonos services, not just Apple

I definitely don't have a serious use case for video distribution other than the fact that my house is wired for it and everyone seems to do it with home automation.  I've been squarely in the DIY camp for a long time and want to get into the higher end/more reliable Control4 world (and not have to deal with it myself).  I think video distribution was huge when everyone at the high end had $1,000 bluray players and cable boxes were like 15x15 hunks of metal--so you were saving money on those devices and getting a cleaner look by using video distribution, rather than just using it to synchronize your viewing across devices.   Now, cable boxes are 4" boxes that you can stick to the back of a TV, every TV has every major streaming service built-in (or a Roku stick is tiny and can be hidden).  The major use case for residential video distribution seems to be dwindling.  But the reason to get it for me is to have everything work seamlessly with Control4 because if I'm investing it it, I want to go 100% in.  But it sounds like there are other ways of doing that that are worth exploring too.  Video distribution is certainly not cheap...

As somebody mentioned before, central distribution made a lot of sense when devices were bulky and expensive. Is it always necessary? A Roku device that costs a maximum $99 (often way less) that can offer access to pretty much any TV service needed, including core channels, live sports (using for ex YoutubeTV, Sling,...) and obviously all movies and TV series streaming services (Netflix, Hulu, Vudu, Apple TV, HBO Max,...) with minimal limitations of concurrent streams. They are tiny and perfectly controlled by Control4. Most users don't play DVDs anymore and don't need access to a Satellite or Cable receiver thanks to services above. 
One caveat is audio and it will depend on each situation. But again, there may be very elegant and cost effective solutions to have high quality audio for those TVs, well managed by Control4 without the need to deploy a complex and expensive HDMI matrix...
I am not advocating against that approach but a strong internet connection, solid WiFi coverage, a few Roku devices, possibly an Audio Matrix and most importantly a great Control4 programer/installer may be a great way to save a lot of money, minimize complexity (and ongoing support costs) and offer an excellent user experience. 

Generally, Wifi 6E requires new hardware because it requires a new Broadcom chipset...  See https://dongknows.com/wi-fi-6e-explained/