Water change is Key, plus cleaning canister
If you can keep it clean, and if the otos don't go after the discus slime, you are probably OK. It sounds like a lot of fish, overall, so you'll have to work to keep it clean.
Your discus ratio is 0.5 using 25% water change every other day, not including any biomass of the other fish, and 0.6 is the norm for planted tanks (see SimplyDiscus.com for how I got this ratio). So, you need to commit to that every other day all the time, or steep up to 30% or better even.
The ratio is (#discus)(days to water change)/(water change ratio)(gallon tank)
So, you have (3discus)(2days for every other day water change)/(0.25water change)(46gallon nominal tank size) = 0.5 without considering other fish
If the other fish are about equal in size to one discus or two, then you ought to add that in also, then adjust the water change volume and frequency to keep that ratio to 0.6 or below. And you still have to keep it clean, wiping down glass and vacing up mulm and cleaning canisters often and any prefilter on the canister can be cleaned daily which will help.
Member AGA, HAS, NASH
110G, 10 adult discus, barebottom with plants on wood
58G, 3 adult discus, barebottom with plants on wood
59G thickly planted tanks, rummey nose tetras, kuhlies
300G goldfish pond outside