Finally, a 100 Girlfriends art on here.
Also, yeah, those two are very gay/bi for each others. One of the more obvious proofs of that is in the kissing zombies chapter, where Rentarou first tricks them into kissing each other, causing them to go into a frenzied make out session with each other. Then, at the end of the chapter, Rentarou now has MORE difficulties physically seperating them apart and making them take the antidote because they are so focused on kissing each others.
Now I'm going to try to find and request a pic of Hahari x Mei, since it's another pairing that gets a lot of ship teases too.