What's your opinion on this story for a graphic novel?

I'm thinking on eventually starting my comic, but I'm not really sure about a storyline (comments & advice welcome). this is what I have so far:
"Unusual Circumstances"

It is a story of a group of people that have banded together because they understand each other's differences (but that's not important) and they are trying to help each other discover their past and solve their problems.

the are as follows:
John: The de facto leader and mediator of the group. A few years ago he accidentally interrupted a spell cast by a bunch of preteen witches in order to summon a demon specializing in giving women pleasure, but instead they called one specializing in violence which promptly possessed John. John is usually able to control the demon but when the demon breaks loose the results are always a disaster. he is currently trying to find a rabbi or a priest or something that can exorcize the demon. due to the fact that summoning has been banned for centuries, one that can preform exorcisms is very hard to find (which gives one an idea as to the amount of trouble those pre-teen witches are in).
Max: an androgynous elf-like person with strange abilities. (He/She) woke up one day in a middle of a crater in a meadow with no memory. nobody has ever seen or heard of anything like (him/her) so Max is trying to find out what (he/she) is and where (his/her) home is, whether on a different planet or in a secret forest. Every day Max rediscovers a new ability, usually during an event that would kill a normal human.
Luna: Aside from her silver eyes she seems like a normal gothic girl. She claims to have the ability to see others as their true self's (one's personality physically manifests to her), which has allowed her to escape the last five mental institutions. She is currently trying to figure out why she is what she is. (this was originally going to be just a story about her in a quest to find her sanity in order to leave the mental institution, but that will be rolled into a flashback cutscene)
Tito: a chihuahua. He used to be a human but was somehow turned into a dog. he still has some memory and intellect from when he is human, but otherwise is a fairly stupid dog. Only Luna knows that he is not just a dog but she doesn't give a shit. What is human in him is following the group in hopes of becoming human again.
Candy: a slut. she has a story of her own but refuses to share. the others only let her come along because she is useful for getting them into places, out of situations, eta. John and Tito have a massive crush on her, and Max is off/on. Luna doesn't care about the attention the boys give to Candy, which pisses off Candy big time.


aaaaaand that's what I have so far. Ideally the theme will easily transition from ridiculous to serious; and I haven't decide on a setting.
thoughts? as you can tell it will be rated PG-13.

Aren't you concerned someone will "borrow" this as their own before you have a chance to write it now that you've deposited it on the inerwebz?

Why don't you give it a go mate?

Oh my that sounds quite graphic for a novel :P