Swordtail maturation

Three months ago (June 4) our golden colored female sword had a batch of about
50 fry. They were kept in a 20 gallon tank, with a few guppy & molly fry.
About 6 weeks ago, I moved some to a 55 gal., and they've grown faster than the
others. My questions --

* None of them have developed swords on their tails yet (altho some are
visibly male w/ developed gondopodium). Will the swords develop later on the
males? At what age do the swords usually develop?

* Is it possible they aren't swordtails at all? I'm sure the female came from
an LFS tank that had similar males w/ swords in it, and the male sword in our
tank certainly was attentive to her. The fry's bodies seem long &
swordtail-like to me, but I'm wondering if maybe they're not swords at all and
actually platies (doesn't seem proper body type), or some type of orange-yellow
molly (is there such a fish?)

* There seems to be an extreme variation in body size among this group of 3
month old fish. The largest have grown to about 1.25", while some remain tiny
at about 1/4" (not much longer than new-born mollies). Will these runts grow?

* I'm wondering if the fry that were kept in the 20 gallon & which are smaller
than those in the 55 are permanently stunted, or if they will eventually catch
up? If not permanently stunted, any suggestions for encouraging proper growth
at this point?

Any insights would be most appreciated! -- Jim