actually ur allowed to play Polmerization on the very first turn, its ur loss if u can negate or stop it
there is nothing in the rule book sayin u cant do that, that is why ur not Allowed to attack on the very first turn because of things like that
and ur 2nd question, wat do u mean? remove from play an active spell or trap card? why would u want to remove it? its just sent to the grave, u can discard a non-used set spell or trap card, because ur not using it, but u cant just discard an active spell or trap card, if Royal Decree is up u cant just say oh im discarding this, it has to be destroyed before its removed
anyways, the first move is always the best for a E-Hero/Neos-Spacian deck, i always loved goin first cuz all ur opponent can do is watch as u make a big move, the only thing ur not Allowed to do on the first turn is Attack, thats it, but if u can fuse, set down some good spells or traps, get a Jinzo out on ur first turn, then u surely got urself in a good spot, an one hell of a hole for ur opponent