Regarding Capabilities this was raised with the panel Solid, ACL's and the future but AFAIK quickly put aside.
Imho, the panel should really reach out to @cwebber who is expert on this, and can explain pros and cons very well. Alignment in general with other initiatives is a good thing. In the past the fediverse community has tried multiple times to do this, and Solid was agenda point on multiple SocialCG meetups, but without success. This while there are great combinations with both technologies, and a couple of community projects are (or were) investigating these.