If I have a Hamiltonian circuit, assuming that cutting the max weighted edge resulted in a Hamiltonian path.
Is it guaranteed that the path would be minimal too?
If a Hamiltionian path is simply any path that visits all vertices, then removing any edge from a Hamiltonian circut results in a Hamiltonian path.
But I assume you want the shortest one, in which case the answer to your question is No.
Take for example a square with one diagonal, i.e. something like this:
A --B | /| | / | |/ | C---D
Now, put a large weight on the edges $BD$ and $AC$. That way, the shortest path going through all vertices is A-B-C-D, but the shortest (and only) cycle is still A-B-D-C.
I presume your circuit is a Hamiltonian circuit of minimum weight. Then removing any edge of the circuit will produce a Hamiltonian path from one vertex of the removed edge to the other, and it will have minimum weight among Hamiltonian paths between those two vertices (because if you had a lower-weight Hamiltonian path between those two, adding back the removed edge would give you a lower-weight Hamiltonian cycle). However, it need not have minimum weight among all Hamiltonian paths (see the other answers).