Hey all new here

Info:
I have two tanks, one is a setup Rio125 with a pair of GBRs *that have laid 3-4times so far, but no luck* 2 zebra danios, 4 corydoras, loads of guppies, and I've bought BN plecos 3 times and all seem to die on me :/.
Anyway, the second tank which I bought last month, is a Rio 300

So far I've bought 4 bits of mopani wood some small and the others medium. A bag of black sand *will need more*
At first my initial plan was to have a stocking list consisting of a pair of angels, 10 corydoras, 4-5 kuhli loach and try a pleco.
But ever since seeing a baby gold severum at one of my LFS I've been swayed over to them :/
So would I be able to house the current stocking list and a severum?
If so, which option out of the 3?
1. Original stocking list with one severum *female most probably, for size reasons*?
2. Original stocking list without severum?
3. Pair of Severums and try to work out what other fish?
I will hopefully be washing the sand this Thursday and putting it in thursday too

So let the ideas flood in
