You do know you can use the cheat house to get nearly everything right?
Tips for early game; (honestly more or less the whole game really)
1- Avoid combat while raiding cheats for equipment
2- Get healing and elemental spells on Sunny and Tommy. (Tommy's a Spellblade, thus usually more useful casting spells. note: sometimes the sword is more useful.)
3- Angus is (for much of the first and even second part of the game) even more useful than Kiba in combat (especially after unlocking all elemental attacks; btw the light element attack is the crystal in the portal tower for were you star and/or end the game.)
4- Stella is a bit of early booster that falls off, she's like Tommy in that she is a Spellblade, unlike Tommy or Sunny however has no real mp regen skill making her more of a physical fighter once her mp is depleted.
5- Although made easier with the stat boosting the game can be beaten with the right equipment, healing items, and playing smart (like any other game really.)
6- Endgame fun tip - funnily enough both of the tougher Vamps have a major weakness (crippling pussy addiction) Sunny using seduction makes the fight you beating the said vamps to death, while they don't fight back... for the entire battle.
(unconfirmed 7th) the boss for the final ending path will likely suffer from said crippling pussy addiction too.