Is it appropriate to include a List/Summary of Theorems in a paper?
If the lemmas and theorems are unrelated (unlikely) then a list might be fine. But if the purpose of the paper is to prove the main theorem(s) then giving that purpose and naming just those in the introduction is probably more standard and easier for a reader to get a sense of purpose.
So, my guess is that your second suggestion works better. If there is one main theorem then focus, primarily, on that. But if one or two of the others has some independent use then you could expand a bit.
Mathematicians are used to following a train of proof through a fairly long argument, but knowing the goal ahead of time can be helpful.