I think Richard would definitely have heard about how Thomas is doing, possibly he could have dropped by to check in, under the pretenses of work related things but also because he does like to know that everyone's doing okay.

Richard's the type who would definitely say a good morning or lift his hat to the Welcome Witch as he came into the Ministry, and he also could have spoken to Sarah while he was a lawyer.

I do believe that, at least most of the time, Richard is the type who leans towards giving WC kids/adults more of a chance in the world, but also that that gives him a lot of backlash in the political world, so he'd be more careful and police himself. I think he would've gotten on with Jude while they worked as lawyers.

I think Ari and Richard could've been school friends, especially if they were both studious