Recover Your Unit HP
When your unit has whatever HP that is less than 8, have her on your territory, then wait until her next turn. Save on that turn and then load that file, this gives her an extra +2 HP, repeatable until full HP provided to save again after reloading.
Unlock Costumes for Each Character with 30 Points
Save before defeating the last enemy on map. After the last enemy is defeated, skip through the story to get to the suit shop. Choose a 30pts suit and purchase it(e.g commando suit). Reload the last save file and go to the suit shop again, you will notice you have 30pts left with commando suit already purchased. The same applies for the 10pts suits when you have 10pts.