Is It Possible To Have Both Residual & Intelligent Hauntings In The Same Place?

Yes, the evidence you gather at the site will let you know which is which (whether you get intelligent or cooperative answers to questions etc.)

While I am "agnostic" on residual haunts, by common definition there is no reason that a location could not contain both and by popular theory a place with the conditions that allow for a residual haunting would probably have conditions favorable for the intelligent variety too.

It's like asking if a caserole can have two types of cheese. Sure...it just depends on which recipe you go by.

It is perfectly possible to express two or more entities in the same place.

Absolutely! For the experiences I've had I would say the ratio is 1:5.