Unlocking Face versions of Heel characters:
. Noble Rose -Defeat Evil Rose with Reiko 10 times, then win the reward match.
. Yasha -Defeat Benikage with Anesthesia 10 times, then win the reward match.
. Becky -Defeat Candy Cane with Miss Spencer 10 times, then win the reward match.

Unlocking the Heel version of Face characters:
This is more time consuming, as you must win the singles championship title from a face character (thus giving you the Reward match to unlock her Heel counterpart). Refer to "How to acquire a Title Shot for more information

After winning the title for the first time, all you have to do is pass the title off to the character you want to unlock (by LOSING a match). Then continue as normal and you'll get another championship match after fufilling the requirements again (this time against the character that 'beat' you for the title). After that, another rewards match will pop up. Repeat as nessecary.

Unlocking Swimsuits
This one is actually quite simple and it can be accomplished quickly. Just take any character, go into the Customize section in the Locker Room and put on her swimsuit. Head out to the map screen and compete in no less than 3 matches and then go back to the Locker Room. The swimsuit your character is wearing will now be readily available in all OTHER character's Shops to buy (no, you can't buy your own swimsuit), so feel free to Change Characters and check it out. Each swimsuit costs 9000 in game currency, and the colors of the swimsuit can be changed when selecting a character (just as with any outfit).