There are, of course, different ways of letting the party be part of conversations, and there have been discussions about this on this forum before. Thinking of single-player, personally I’m not a fan of a solution that would automatically use the best skill check in the party and would like to have my low charisma fighter try to persuade if I want to. But I really, really would like to be able to swap to another party member and have them interject if I preferred that.
Absolutely in favor to not automatically use the best skill check. There are dialogue options which skill checks I want to intentionally fail in order to get additional and alternative dialogues and this possibilties should be kept.