2 always two with out question. You will not need that much output for music. My JLs run at about 10-o-clock on the dial with 90db speakers.
How do you plan to connect them? that is far more important than what sub you choose.
Low passing them under your mains is fine but not ideal. It is complicated to get right and honestly makes things worse imo. If you highpass you can take the system to another level entirely. There are lots of cheap ways to highpass (mini DSP, etc) and more expensive two channel oriented ways (JL-CR-1, wilson sub controller, Bryston, etc).
anyway, I would add SVS to your list. They are a better sub imo. The SB16 ultra is an impressive sub ($2300ish) with lots controls and a bit of built in EQ. They can be controlled from a phone app. I think they are comparable to the fathom line at 1/2 the price. They have cheaper options that sound as good really, you just lose features. I personally run JL which sound good but I can’t recommend them due to reliability issues.
For me I would step down to the Sopra 2 and add a JL CR-1 (active analog controller) and two better subs of your choice and never look back. Passing to the subs around 60-80hz makes for a very impressive system. This will allow the bass to perfectly match the room as it is 100% adjustable. Looking at the Sopra’s measurements I would highpass them right around 65hz as a starting point. Try 10hz lower and 10hz higher and see what direction you like.