That first catfish head wouldn't go down backwards; it kept jamming up with the pectorals locked open, one sticking out on each side of the mouth. Using those spiny little bastidges as food, dead or alive, seems foolish due to the possibility of internal damage to the big fish. I have used many bullheads as food for predators in the past, always humanely pre-killed and frozen...and I would never offer them without first using pliers to snip off those wicked pectoral and dorsal spines.
The single Aba Aba I tended for a period of time during my stint as a petshop employee...a looooong time ago...would eat anything offered; live, dead, frozen, dried, whatever. It also would absolutely not tolerate any tankmates of any species, usually attacking within a few seconds.
We never tried, but in hindsight I wonder if it could be kept with very small schooling fish, like many large predators can. Small enough fish may be beneath its notice, and not worth pursuing; I'm talking about small tetras, guppies, etc. Might be worth a try?