1. Yes. Pollen is capable of staying airborne for quite some time, and one grain of pollen can make one seed.

2. IMHO (and experience) a female throwing-out male nanners is a defensive genetic response to stress, no matter what the strain. If the strain you want to hermie has been a stable strain before you stressed her for the pollen, the seeds should be no more unstable than the parent. Going hermie is a genetic response you'll find in all strains, (even the stable ones) but some strains require more stress to trigger the event.

I have femmed a few strains, (C-99, Potent Purple, Sweet Tooth, Swazi, BubbleGum, Shishka Skunk, Pokerface, Inca Spirit...) and none of the seeds have grown to be a hermie. Zero, zilch, nada. Unless you consider the few 'femmed' beans out of a hundred, that show male preflowers. (not female parts) These I eliminate immediatelly, but are few-and-far between.

Having said that, I do not cross-feminize. (using the femmed pollen from one strain to polinate a different strain.) I also do not fem plants from femmed seeds.

Also, femming seeds isn't something I do out of necessity. It's more like a hobby. It's something to do while praying for my ladies to mature faster. Before femming any strain, I always make sure to have plenty of regular seeds, in the unlikely event of failure.

Most of the time, I'm willing to bet, it's beginners error that triggers the plants genetic response to stress, not the occatioinal weak strain.

3. If you have the space in your veg room, a mother plant or two will give you a head start with the clones, but if something were to happen to your veg room (lights fallin on 'em, bugs, unseen light leaks, mildew, mold, vacation...) and you have no seeds as back-up...you risk losing the strain.