Would fitting a T-tail on the 737 Max make MCAS unnecessary? This is pretty far out, so I just pose it as a question for notion or ideas, rather than conclusive answers.
Considering the differences in flight characteristics between the Boeing 737 Max-8 and older models demanding the creation of MCAS and subsequent problems and crashes;

would it be possible to bring the characteristics back into the existing 737 envelope by lifting the horizontal stabilizers to the top of the tail, rendering MCAS obsolete?

Would certification heritage from the 727 allow for such a change without demand for recertification?

If so, to what extent?
No. A t-tail would worsen the characteristics of the airplane. While not necessarily a horrible idea in its own right, the already-nasty slow-flight/high alpha/stall characteristics of the aircraft that necessitated MCAS in the first place would make this idea dangerous. The pitch-up tendency could lead to a stall, which in a T-tail can lead to a deep stall. A deep stall is a condition in which the wing blanks the tail surfaces. Since the tail is no longer effective, recovery is EXTREMELY difficult, if not impossible. So really, a T-tail offers no advantages and may actually be MORE dangerous. Regarding your second question, no. This proposal is such a drastic departure from both the 737 and 727 that recertification would be unavoidable.