Chipping in, but yeah. On Very Hard, her regen got completely countered by setting her on fire, so my tactic of choice was putting up Last Sanctuary and alternating between Primal Fire and Soul Saber to keep my MP topped up.
Between Last Sanctuary (10% HP regen/turn and -50% damage) and the Healing IV's 5% HP/turn regen and Explosion IV's 3,3% MP regen you should be able to hold out against most enemies you face.
Also, be sure to buy the Gym Bloomers once you get 10k to do AGI training and swim for +20 HP (free swimsuit after saving Hibiki) each school day. It may not look like much, but it's free stats and they do end up adding up over a playthrough. You can top it off with a Mission or dungeon run at Night to keep Domination down. If you need money, the enemies in Renegade Base are for the most part humans, so they drop money and there's a couple of women to save for City Rep as well.
For farming, once you unlock the Downtown area, immediately go to the Suspicious Bookseller and buy Collection Tips for 50k. The passive you get from it gives you a chance to get two items from a harvesting point instead of one and GREATLY speeds up the crafting grind. I cannot recommend that book enough, best 50k you'll spend all game once you've got Celesphia (35k) crafted.