you have the raphael and senegal in your 55g. why add a BGK, knowing it will outgrow the tank, or the senegalus biting the fins off of it? if i were you, i would aim to get a surface swimmer instead, since the senegal and raphael reside at the bottom, such as butterfly fish/ congo tetras.
ornates would surely get eaten by the RTC. congicus bichirs, unless you manage to find one 30'' above which is rare to obtain, i would not add them to your pond. heck, why add bichirs to your pond? you have large predatory fish like the RTC which would out compete the slow feeding bichirs for food. if i were you i would aim to add in fish that are compatible with RTC, like other catfish such as tiger shovelnose.