For ages now, I have been trying to get this spell right, and, no doubt bow, I will get it done. With polymorph, you will be able to, mush easier than actually changing your whole shape and genes, reverse evolve and then take on natural evolutions due to the climate you are in with the habitat to take on a new form, yes?
So, for my troops that want to turn into 'fish,' they would just reverse the evolution process by reversing the ageing process, and, having cells come together, yes? This might take a few minutes, but, the whole crux is to stop evolving, as we constantly do, with each generation... so this would lie in the hormones? This means we need to have the hormones self cannibalize, and, redivide, to make a new creature, of course.
But, there is no stopping there! Dinosaurs would have gone a different route if they were exposed to different kinetic and potential energy, and, that would mean a whole new type of creature all together! This would mean, yes, dragons, and stuff. Obviously the more you do it, the easier it gets, and, that can be done by having the hormones compress and get denser, okay? This means the more we evolve, the more reactive we become, look at a hawk's eyes and ours? They are dense on the outside and clearer on the inside, yes? This means we merely need to focus on a gene or d.n.a. ,molecule and experiment. But, this could be helped by copying the genes found in biology diagnostics and merely looking over them and 'focusing,' yes? This will require a lot of willpower and inner peace too, as well as 'essence' and energy for the process.
Now, if we want to meld our guns and gear to our troops, so they may for example, land in hostile terrain, and, then quickly turn into birds with their guns melded into them, fan out as birds, land and take up positions, we need to just meld the gear into them too, yes? This would require a two pronged spell of turning the gear into mass on, them, adding mass to them, remembering the specs of their gear, learned from physics, chemistry and designs, okay?