So this is a headcanon thing I’ve been working on for a while, which may or may not end up being used for some kind of project if I ever stop being too lazy to start it.
 
Basically it’s my attempt to take all of the Doctor’s various companions over the course of the show and find analagous characters from FiM to act in their stead as companions of Doctor Whooves. And it’s not just random ponies thrown out there either; Every one of them has something in common or some kind of comparison with their DW companion counterpart, either in appearance, personality, circumstance or story. For instance, all of the non-human companions are represented by non-pony characters. And to answer your first question, I left Susan alone because I’m already playing pretty fast and loose with the canon of two different franchises and I’m not about to start drawing imaginary family bonds between pre-existing characters.
 
And to answer your second question: Yes, I did just turn the Wonderbolts into UNIT. What are you going to do about it?
 
So yeah. A whole lot of thought poured into something I’m probably never even going to use. Feel free to cop any of these ideas if you think you can do something cool with it.