Will & Grace are J and P, it's quite obvious in many of their fightings for many things. I guess he is ISTJ and she seems INFP but she's not typable at all.
Jack is clearly ESFP, while Karen absolutely not realistic as a character, still I would say that ENTJ is her best fit.
If I am right, it's curious that all of them has the Fi/Te axis and nobody has Ti/Fe.
The "funny couple" is composed by extroverted with Se/Ni axis, while the protagonists are introverted and with Si/Ne axis.