Sure, it can be done. You just want to keep the ajuga from covering the exposed iris rhizomes, so may take some frequent monitoring once the ajuga becomes established.

Any tips on growing ajuga, have not had much luck transplanting it

FWIW, I have found ajuga to be very aggressive and hard to get rid of. For me it was very vigorous and very hard to remove once I decided it wasn’t my cup of tea.

I’ve always found iris to be pretty self sufficient though and I would imagine they would be ok together