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.