I currently have an aisle in my house that I would like to leave open for a while, but with the possibility of installing an interior door there later.
Who knows this: if I plaster the frame on the inside, I will lose some height at the top as opposed to other doorways.
Will I have enough clearance later to install a box with a standard size door?
I would just measure it. A standard size door requires a height of at least 2.01m. Otherwise, you would have to shorten the soffits and door frame or knock down the plaster.