Update!
Ended up losing all my known CB bichirs awhile back now. Both teugelsis and the delhezi sadly passed. No identified reason. None of my fish are showing aggression, everyone eats the same, WCs every 5 days, parameters are good, filter's bacterial colony is strong. I've wracked my head over it all, and can't find a fault in the care that led to them passing - especially since the other seven polypterids in the aquarium at the time are all healthy and growing.
Since my last update, I sourced 2 WC retros from an LFS, and just today picked up a little delhezi and weeksii from a listing on kijiji. They had a retro and palmas as well, but sadly they were already spoken for. Hopefully the deal falls through and I can pick 'em up.
125g stocking is as follows:
1 Paratilapia polleni (presumed male)
Pair of WC retros
Blind female weeksii
female sen
4M/1F ropefish
Then the new del and weeksii, both of which are a liiiitle too young to sex IMO. I know people will say female when they see the weeksii's pic, but I thought I had 2 female retros for awhile and then one week the muscle around the anal fin really beefed up.
Here's some pics!

My old, blind weeksii gal with the new delhezi

A better photo of the new delhezi

A photo of the new weeksii in the old keeper's aquarium. Notice the filth. The water smelled of ammonia as I brought it back, took the toll road to get home ASAP. Thankfully bichirs are hardy. Could've probably kept them on a wet towel with a mist bottle.