I think it's absolutely fantastic they you are not only seeking advice, but taking it as well. Many people (including myself at some point) only take the information they want.
Personally I think I got lucky with my EBJD experience. Neither died and one got to a beautiful 6" before I reghomed him. That being said I've heard many horror stories about them from other keepers.
As for oscars, I've never had the pleasure of keeping one simple because when I had the appropriate sized tank, other fish made the cut before the Oscar. You'll hear arguments on weather a 75 or 125 is the "minimum" tank size for one, and both sides have good points, but for starters I think your 90 will work very well.