so...
a hero with kobolds is good), but... it's not quite drawn correctly). Wouldn't it be too difficult for them?) and two wheels on the chair also don't look good).
or you could make a throne (carried on a litter), which is carried by 4 kobolds)... or make something like a mini-carriage, open, and pulled by two ogres))).... oh well, it's a pity I can't draw an example for you)))..... levitation is also not bad, but some heroes are humans). Does that mean they were taught this by ill-ys and behirs? __))... in general, we still need to discuss it)).

regarding harpies...
they live in caves and underground, so they should be more animalistic). Predators! ))
and they joined the Nighonians more for security reasons, because refusal could be fatal for them))). So they decided that it's better to join than to be killed).
P.S. They have their own queen))), although more like a leader)). And they are controlled by mind-flayers))).