Is there a way to make companion mobs that can follow you through dimensions!? Like, for example, a Clara that can enter/exit the TARDIS by following you.

This is a question, not a suggestion.

At the moment, no. But maybe in the future.

I  myself am hoping the ability for mobs to enter Tardises get added. We'll have to see

 I know. I meant it as a suggestion. Also, wondering if it was doable.

I am also surprised how fast the are updating the mod. To have already announced new TARDIS interiors and Handles.