When I start leveling new toon, I use all needed factions Mandates from the start, and with that approach (and also killing every hostile thing on a map), I hit Revered status with Black Legion to the mid of Elite. And when I’m doing Oucast quest on elite and ultimate, I have rep reduction with Legion. That is annoying and sometimes I cant get BL gear when I need it, I got to go further, kill stuff\do quests before. I think that after hitting revered status, rep number should be locked, or maybe better have inner over-threshold counter. Cause its really strange: I got revered, then done some quests for +2k extra rep, and then one little -100 makes me fall down. Really annoying.
I always keep 1 legion bounty ready to cash in to counter that, but I agree its annoying. Same for homestead if you give supplies to legion
Don’t even talk to her on Elite and Ultimate until you get what you need from BL (typically at least a dozen of each augment you might possibly use). Then do her quests for xp if you want. If you have a mandate you should hit Revered with Outcast by level 70 without farming or quests.
The hit to Homestead is really minor and one quick Mogara run should solve it if you absolutely need some Homestead gear.
I typically turn in the supplies to the Legion after killing Commander Lucius. Get the Outcast quest, do the quests up until you get the one to fetch the fang. On the way to get the fang, you regain Homestead’s rep killing the beasts. You restore the shrine for a devotion point and return the fang to get your Outcast rep. Stop there with her quests and go to Necropolis. Once you go there, you regain your legion rep. Everyone is happy, and by the end of Elite Logg, you are revered with everyone but the new AoM factions assuming you have the mandates.
Just keep Immolation for after the 3 Rogue Dungeon it solve all by itself.