Looks great and with plants, would be smashing!

I, of course, vote for discus and that would be perfect for ten (young ones are not very expensive and if well feed, will get very large!) With a lot of plants and extra filtering, water changes would not be all that bad; once a week should be fine (amount depends on nitrates levels you measure.)

A very large school of cardinals would work great with discus. Ditto with Sterba's Corys - both these fish will thieve with the 84 - 88 F that is required for discus. Remember, soft water is only required for breeding; discus adjust to hard and basic water.

That said, can't argue with angels - just don't mix angels and discus.