I voted 2. You will see that males have a white or pinkish dot behind their front legs around their 'armpit' area, females will not. I don't know if you can add a betta or not, but I guess it'd be fine. I heard it's hard to feed ADFs when there's other fish cause they're slow eaters and I heard they'll be more shy with fish around. Oh yeah, if you get ADFs be sure to provide hiding places away from the light, they will be more active if they know there's a hiding place to retreat to.
EDIT: It won't let me vote. o.o If I could vote, I would vote for 2.