To the original poster -- you may be better off on AA. MIA is reportedly a bit of a hell-hole, as you probably know, though I think it's gotten better with some renovations or something. AA's Business Class isn't as good as CO, but it's generally easier to get into (no 24-hour rule and less of a need to "protect" the J cabin since they also have F on the LHR flights). They do charge a co-pay, but it's fixed at $250 each way for all but the most expensive coach fares (no copay and fewer miles on Y/B fares), so it will likely cost meaningfully less $ compared to CO (certainly not $1850+miles if you plan in advance).

Not sure where you are going in Europe, but AA flies nonstop from MIA to CDG, LHR and MAD. You can connect on oneworld (BA or IB) in MAD or LHR for additional destinations, although only in coach. Or, you can route via DFW or ORD (both from FLL if you prefer), or even JFK (only from MIA) to a broader range of destinations on AA metal, where you can be up front the entire trip.

Plus, AA has a "gold" and "platinum" challenge, that fast-tracks you to elite status, which would be a good idea. You can potentially earn AA Platinum (mid-tier elite) after one round-trip to Europe. Lots to read on the AA forum about this.