Hello! I'll see if I can't take a crack at answering your questions.
1. I'm not sure of exactly what you are asking, but if you are wonder if one can control steam probably not. At least not without possessing the lore for creating it as a possible Para-Element. So a regular reimancer without the lore for creating and controlling the Para-Element of steam would be unable to control said element, if that makes sense. So it might be possible, but only with some experimentation with said necessary elements.
2. You can indeed only attract those elements or para-elements you command, you would not then attract the soup I think. Then again, it is possible to use attraction to attract the moisture from a persons body, so I suppose it would depend on how diluted it is. If that makes sense.
3. Yep! Most experienced reimancers transmute their res in layers to maintain maximum control of their spells. Like creating a ball of res, making an outer layer and an inner one, the transmuting the outer to fire and keeping the inner as res to control the spell better. You also don't have to commit all the res you generate to just one spell. This one is also answered in the lore.
Hope that help.
EDIT: And ninja posted twice lol.