1) Do you mean the transition and base periods for general endurance? I think you can keep the max hangs. Your legs won’t notice… 🙂
2) No. Likewise, your legs won’t notice the ARC sessions. They’re too local (focused on the forearms.)
The biggest thing to consider is fatigue. The climbing will be more of a recovery workout for your legs, but not vice versa. A lot of general aerobic work could fatigue you for the technical climbing. So those sessions are best done fresh, after a rest day, the first workout of the day, etc.