With "the object" i meant the bytes in memory that make up an object without taking optimizations into account which can ignore parts of it (since, as i wrote, those can interfere with what you are trying to do).

And yes, the compiler made 4 out of these 5 functions to disregard the vtable, but this is again something the compiler did that you have control over - if you are trying to take advantage of such implementation specific assumptions, you wont realistically use optimizations that break these assumptions nor write code that do not follow them.

The only place where this can break is if a library uses its own functions, those functions are inlined in some places and you want to hotpatch them. But that is an issue with hotpatching 3rd party code you have no control over in general regardless of language (it can happen in C too, for example), not just with vtable hotpatching.