You can have all real or all fake, or a combination of both. I keep live plants for helping with the humidity, and because they're obviously more natural. I also use fake ones as fillers.
The arboricola is the one you want, as it is safe.
If you have a veiled i wouldnt put too many fake plants in since they like to eat plants and ingesting a fake plant would probably block up his intestines, real plants should make up the bulk of the cage and they also provide humidity
I can never keep real plants alive very long so all my big setups have gradually transitioned to fake only. I put fresh greens in my veiled's cage for him to munch on so he doesn't try to eat fake ones. He knows where to find them and he expects them!
It's personal preference really. Real look nice and help with humidity but they can be a hassle if they're always dropping leaves and then look like they've been thrashed around in a storm for no good reason.
Using a grow light and pruning the bottoms correctly makes them grow like crazy!! I really like Pothos since I don't have to prune them and with a grow light I can almost actually see daily growth! I can certainly see leaves unfurling daily! My second choice would be a tie between ficus' and dwarf umbrellas! They both grow very quickly and very tall! I like the ficus' as trees, but the umbrellas generally get bushy-er.
If you use good fishing line to hang a pothos or two in the cage and let them grow down you don't have to worry about moving a pot around to clean! The floor is completely bare!