I think the natural way to say this in English is, "Mike is an ordinary man." I think they mean regular in the sense of being ordinary, since most of the sentences are about smart or amazing teachers and doctors and smart Arab women and men and boys and girls, you name it! Swift translators, etc:-)
Yes, ordinary makes more sense in this context. I looked up the word in my small pocket dictionary and it only defined 3aadii as "normal". Then, I went on-line to a few dictionaries and got the translations of: normal, regular, ordinary, common, conventional, average, commonplace... The definition seems to depend on context and with what noun it is paired. "Regular" would seem to go best with "petrol/gasoline" and "ordinary" with "man".
It should be "Mike rajul(un) 3aadii". Mike, because it is not an Arabic name, does not take tanween/nunation. Rajul does have tanween in MSA, but the last word in a sentence doesn't have to have it. The last word "3aadii" doesn't sound like it is being pronounced correctly by the computer voice, to me.