You have a group of very healthy plants and a good assortment. All are popular easy to grow plants.
I receive a lot that look like this or even more overgrown. They look like they are in four inch pots (pots are measured across the top). Surprisingly the plants could stay in these pots longer and still be healthy, but I assume you want to re-pot since they fall over too easy.
Never re-pot into a pot larger than 1/2 to one inch bigger than the current pot even if that pot also is too small. Yours should have no problem going up an inch. This growing season and the orchid should take re-potting well now.
Re-potting oncidiums have two problems. If there is too much new medium around the outside of the plant it dries too slow and rot can develop. This is the reason to keep the pot small. Often I will re-pot a plant like your first one simply by changing the medium if necessary and moving it in the same pot off to the side so that it stands up.
Second the roots are going to be a tangled mass on the first plant. Cutting and breaking roots are scary but really not a big problem.
Remove the plant from the plastic pot by squeezing it and sliding it out. The roots will be growing in a circle around the pot and you will probably not see anything else but roots.
These plants often grow in a half circle in a four inch pot and your first one is doing this. When you have it out of the pot looking at it from the position of the yellow name tag toward the plant you will have the new growth away from you. This is the point where it is easiest to work the roots open. Start at the top and work the circular roots loose. Even though these are extremely healthy looking I have learned to not be concerned about breaking or cutting these. They grow back fast.
Check the medium in the center of the plant. you will probably have to remove Styrofoam pellets to see it. If it looks bad replace it (probably sphagnum moss) by puling it down from the center and pushing new moss up into the void before putting it in the new pot.
If you were interested in dividing the plant you would open the half circle when the roots are loose and gently spreading the bulbs a cutting point will present itself. To re-pot for growing into a specimen plant move the plant to the side of the new pot.
You also can consider mounting these on wood. These plants have a tendency to grow up out of a pot. They do very well mounted.