New Member, Need Help!! (please)

[Hirschy]

ive been collecting orchids for a couple of months now and just started noticing some things that are worrying me (sorry if its no big deal, i have very little idea of what to look for)! below are some pictures of spots that look suspicious, would greatly appreciate ANY feedback!

the first two images are the same plant... there is a straw colored spot that has made the leaf almost see-through... as you can see its the only spot on the plant. the rest of the plant seems happy since its strongly putting out a new sprout of leaves

the third and fourth are of a vanda that i bought knowing it wasnt doing so well... the bottom two leaves are yellow and the roots arent turning as green as my other vandas during watering. the plant is desperately trying to bloom though! (also not looking too good)

lastly is a new vanda i came across, the roots looked fine when i bought it however once i watered it tons of white dots appeared (is this normal for some types??)... it seems to be healthy otherwise and is in strong bloom, looking much healthier than the previous plant mentioned...
sorry if the questions seem silly!