My thoughts are that he's pretty into you. A shy expression of "I like you a lot" to express a deeply held desire is the type of thing I might have done, if given the opportunity. The fact that I'd try to contain such deep emotions in words that don't really say anything at all is also the type of foolishness I'd think of doing, too. Heh.
As far as his smugness, that might have just been satisfaction in having his suspicions (and possibly wishes) of your feelings confirmed. You may have confused satisfaction in seeing you squirm simply with satisfaction that you liked him romantically.
I don't like how he looked away when he told you that he liked you a lot. It either means he's lying (although based on the greater context, that seems less likely) or that he was unable to be present and connect with you as he was expressing his emotions. By not looking you in the eye, he was able to remain in his head.
Honestly, what to do next depends on what you need and want. If you are happy trying to solve the "what does he feel" mystery, then by all means continue on. However, if you are done with the game playing and are ready for something real, I think you've earned the right to call him out. As I see it you've showed him yours, and now it's his turn to show you his.
If you want to tailor suit your approach to compensate for INFP Fi shyness, then by all means, ask him if he shares your feelings, and then give him a bit of time to reply.