Stephen, a new " contributor "of this blog and soon you will read more, ask me:

1. Can I put more than one pair of scalars in the aquarium?! Do not annoy you?
2. I have to remove Botia, Ancistrus, scavengers, and so on??
3. In this case, I can at least leave the only discus that I have?
4. If I remove Botia, Ancistrus, scavengers, how do I meet the latter carry out functions that in the aquarium?!?!?

First of all, lacking the size of your aquarium, without which the answers 1 and 3 are impossible to give. In principle, if you aim just to play the best thing is to isolate the couple more close-knit and leave her alone with some smaller fish, such as the so-called "cleaners" ... BUT NOT the clowns , who are quick to ... more nocturnal predators . Beautiful that they are beautiful ... but to play any kind are disastrous. :-)
You can safely leave Ancistrus and Otocinclus, for example, but also Corydoras if you ... But I would avoid to stay even more comfortable.
If the aquarium is very big, say from 180 liters up to be safe, then you could also take other small cichlids, dwarf cichlids like. If you avoid putting fish, small and fast, as are the fish of the family herd of characins often seen associated with the scalar, then you can more easily assist with parental care of the parents after spawning, as well as a number of small eggs, then certainly much higher.