I think I just made a major booboo

I won't pass comment upon your new purchases as I know little about Malawi Cichlids but something I read after in the thread caused me a little concern,

\"my substrate is a lovely soft coral sand\"

if you already have Rams in here and were looking to add Kribs or, even worse, Macmasteri I would really like to point out to you that Coral sand is hardly the best substrate for any of these fish, although Kribs will tolerate harder water with higher pH at a pinch the other two Dwarf Cichlids are from softer, lower pH waters in South America and Coral sand, being primarily made up of shells of Coral Polyps, is not really conducive to making your water ideal for the conditions required for these fish - in fact Coral sand and gravel is often used as a hard water buffer to raise the hardness and pH of water...exactly the opposite of what you would ideally be trying to create. Perhaps someone could clarify also about the Banjo Catfish, I think, but am not sure, that these also come from soft water too?
Now, for your new Auratus the use of Coral sand or gravel would be fine as Lake Malawi water is hard and alkaline...but you mightn't be keeping those anyhow? I have read about these too and there have been a few posts on this Forum regarding them if my memory serves me right (use 'search' function to look back). But a 'normal community fish' they aren't - this could actually be said of many, if not most, Malawis too...they're just too boisterous - much the same, actually, could be said of Kribs when they get the reproductive urge upon them - they can be little demons too.
They could be fine for a while but I think you shouldn't make any long term plans to keep them, and anyway a 65 ltr tank wouldn't be really big enough anyway.

Sorry to be being the bringer of bad news, but these are a couple of things you ought to be aware of.

John