The first is a cattaleya. The second is Oncidium. The next two are Dendrobiums. And of course we all seem to agree the last is a Phal. All are hybrid types. The best way to determine though is to smell the first because its hard to tell just by the pic. Catts have a very strong aroma to them that sets them apart from the Dendrobiums. As for repotting, snip any roots that appear discolored or rotting for these can later cause problems in the regrowing phase. A good orchid mix soil that already contains fertilizer is ideal, however small amounts of liquid fertilizer may be used.