Writery question

[mrv3000]

So in writing SG-1 fic from, say, Jack's POV, I would always make every reference to Sam be "Carter" instead. Even the dialog lines. For example:

"Sir, I'd really recommend not going commando on this mission," Carter said, an amused smirk on her face.

Jack blinked, wondering how she could have possibly known.

Just because to Jack, Sam = Carter.

Switch over to Doctor Who. So I'm writing a Rose POV fic that includes her mum. I'm getting twitchy because I *want* to write things like "Jackie said" but Rose doesn't think of her mom mum as "Jackie." But also saying "her mum said" all the time sounds weird as well as plain old "Mum said."

*FLAILS*

Any suggestions? Ideas? Commands?

ETA: I'm now thinking I can never have Jackie in any fic. Ever.

ETA2: Like, the above is honestly the way I've been writing. See here for an example. I have *no* idea where I got that concept from, but I like doing it that way. And...no one's ever smacked me for it so I never thought anything of it. :-\