I'd assume Whimsical means two relatively healthy people.
I've never seen an INFJ and an ENFJ interact, but I don't see why they shouldn't get on just fine. They might butt heads a bit, as Js often do.
I imagine it would be a similar relationship as the kind you would find between INTJ and ENTJ, or INFP and ENFP etc etc? In which case I'd say, sure, why not. There would be some duplication of efforts and skills but they could make a great team nonetheless.
"There's no need to be embarrassed about it, Mr. Spock. It happens to the birds and the bees!"
I know a married couple with this combo. I found out recently that the wife is an ENFJ and the husband is an INFJ (my first IRL encounter w/one). They seem to have this best friends / soul mate thing going on.
"Charlotte sometimes dreams a wall around herself. But it's always with love - So much love it looks like everything else. Charlotte Sometimes - So far away, glass sealed and pretty." - The Cure
My INFJ friend is married to an ENFJ and says it's wonderful. However I've never met him, so couldn't observe their interactions. My mother is ENFJ and her and I never run out of things to talk about and are complementary in our ways of dealing with people (she's more forthright, I'm more behind the scenes.). I expect it probably works out pretty well.