Subclassing pathlib.Path
@Danninno asked us to close off the question, to be honest I forgot about the request for a bit until recently (I've been using the wrapper quite a lot). 

Answer

I see that within my own code I went with Option 4. Mostly for the reasons stated in the question. It turned out to be the better fit of the 5 possible options. Option 5 was/is a close contender as it's more OOP'y but it does generate a crazy class structure to simply hide an implementation detail.

Motivation/Discussion

When I originally asked the question I was hoping for bit of a fight/haggle/explanatory answer (Even if I received an opinionated one i.r.o. the forum rules) or atleast a good argument as to which method was the better/worse one. Mostly so that I could improve my decision making process. I see now that some classes in Python are done by it's developers to showcase certain features (After all they like to play/push the bounds somewhat). In this instance Path is constructed in such a way as to avoid the use of Metaclasses (I might be a bit off here, as it's been a while since I looked at the source for pathlib). Another example of this "playing" is seen in the NamedTuple implementation which essentially evals a string to implement it's class, which eliminates any implied inheritance.