If the rest of your plants remain female, you won't be dissapointed with yield. I would say at least 1oz, 1 1/2. Maybe more. For your first grow, you are doing fuckin awsome. Wouldn't change a thing. As for flowering time, looks like you got some def. sativa dominants. Yes, you are right. Pure sativas can take up to 15 weeks to finish, but I heard pure sativas are hard to come by. Since you have bagseed, might be a hybrid. Just check those trichs when the time nears. Bravo though. + rep on a fantastic setup.