Not a nice challenge but we can combine this with some other challenges.
The rules:
As soon as you get the wolf form (must get get it) you cannot change to Alucard anymore. Be in wolf form until you reach the other forms. However, you change back to Alucard when:
= buying
= regenerating MP (you must put your hands off the controller if you're going to regenerate)
= going to an elevator and teleporter
= entering blue doors
= doing divekick trick
= making wolf rise
= saving
You MUST not change to Alucard. Kill bosses while in your animal/mist form, glitch while in form. Gas cloud is okay since some bosses is immune to it and it'll waste your MP and when regenerating, you cannot move and the boss will kill you.
Any question is welcome.