No i don't think there is anything nearly as compatible as Danios, I mean you can try rainbows but it would be a risk,
Although keeping cichlids is a risk and keeping a crayfish with fish is a risk so you never know it may work?
If you have kept the crayfish with the convicts for a while now then i'm guessing they should be ok,
ye ive had the cray for a gd few months and no problems with 6 convicts, ye i might try the rainbows ill have a chat with the lfs and i really like the senegal are they aggressive? what fish do you have?
senegals aren't really aggressive, but they are predatory and will attempt to eat anything that is too small,
as for my fish i have a number of cichlids including a Nicaragua cichlid, severum, green acara, sajica, t.ellioti, geophagus surinamensis and pair of keyholes.
as well as 2 bichirs, (a standard and a albino), a snakehead, a black ghost knife, reed fish and more...