Discus grabbed my attention when I went up to a local owned fish store because they were so colorful and just absolutely stunning. Then I did some quick web research on them and I was like OPE no. I will be sticking to some more beginner friendly fish especially after your story. Your girlfriend at that time must have felt awful. When I was a child(Only probably four at the time) and my dad had his tank full of cichlids I had been left unattended for a few minutes and found armor all leather car seat cleaner poured it into his tank grabbed a ladle and made "soup". I still feel bad to this day.
Your basement fish rooms sounds AWESOME! We have a few spare bedrooms so eventually I want to do something similar and make one of them into a full blown fish room. I live in an old house though that is lacking outlets as well so that's my only issue. (And saving up the money for all my fish stuff. It seems like we are always fixing something on the house or coming up with new house projects lol) Luckily my boyfriend is an electrician though I don't know how thrilled he will be updating our wiring ha-ha!
I used to breed purple Moscow guppies as a teenager to pay for my betta set ups. I was lucky I had a dad who was fish obsessed so he supported and helped me with all of my ventures. We had a local fish store that would purchase them but now my closest non chain pet store is an hour and 15 minutes away from me which is a bummer.