sorry for not being direct severum boy
its ok, ill look on the web for a shoaler fish that will look
I would say 100gallon was too small for silver dollars, and they become ugly when older.
Glass catfish, are catfish not oddballs, and there are far more bizarre looking catfish than the Glass.
I would suggest maybe getting atleast a 150gallon tank, as you have a gibby, which could grow to over 2' and a 100gallon tank just wouldnt provide enough room for it to turn around.
You could look at some of the shark's such as apollo sharks, but these become very aggressive.
I would imagine that the polypterus will eat the Leopard Ctenopoma in time.
As for the 'needlenose' I gather you mean needle nose gars? these are very shy fish and tend to spook easily, so you need a lot of room for them to dart about in, or you could end up wth some damaged gar beaks, resulting in death.
Other fish to consider could be:
- Geophagus
- Clown loches
I had the same problem with my 120gallon tank, trying to find something for the top level of the tank, or shoaling fish.
for the top level I ended up with a flagtail prochilodus, 2 bala sharks. (I know they recommend minimum of 4)
Hope this helps you some what, and I wouldnt buy the fish until you have the tank, as things happen and you may not get the tank, and either end up with dead, or stunted fish, or having to cull them due to not being able to find homes for them, especially the gibby, a hard fish to rehome.