1) just provide content warnings prominently in his journal and in the subject lines of tags that talk about those issues. if the smut is going to involve it heavily, talk to other players ahead of time and be mindful of their personal opt outs and preferences. some people will want to avoid it completely, others may be fine with it. you might also want to include an opt out post in his journal in case people want to let you know privately that they don't want to have threads with him

2) generally fine and nobody cares, ignore anons who say otherwise