EULA is a contract, and any intent is spelled out in the EULA. Doesn’t matter the context of why Mojang changed what they did. The EULA applies to all end users, server owners and players alike.
I agree with @ABDTGaming, this seems more like a separate forge mod than anything such as FriendsOverlay. But to add on to this idea, it could be possible to use Minecraft’s services to track what server players are on, therefore a client-side friends list could be used to quickly join their server, similar to the FriendsOverlay.