You have some nice looking specimens there. You asked about feeding, I agree with Minh, you would want to feed none or minimally to maintain a smaller size.
BTAs are the only host anemones that divide on any frequent basis, and so feeding those can result in divisions, which following a division, one clone will move from the other. Feeding per se doesn't cause anemones to move, it's the dividing that leads to movement.
The two things that would be of most concern for me are nutrient control and allelopathy. You will want to keep a close eye on your nitrate level, always trying to keep nitrates undetectable. Anemones are sensitive to nitrates and though they won't drop dead from the presence of nitrates, they will begin to move and in general not look happy. Skimming and use of a good quality activated carbon can help to decrease nutrient load and allelopathy. Anemones produce a significant amount of bioload from their shedding ("slime"). I personally would not keep haddoni in the same tank with magnifica and/or BTAs. In my tanks BTAs and magnifica didn't make long-term good companions. Eventually the BTAs began to get smaller and not look happy until I removed them. Now I house the mags in one tank and the BTAs in another tank.