The Federation doesn't use money...until it does.
Seriously. That's pretty much it. If a writer feels like putting it in there, they will, and the continuity will just have to sort itself out.
And besides, we have always known (ever since TOS) that Federation credits are a thing. So there's your "pay".
You cannot, on God's Green Earth, convince me that The Federation doesn't work with some kind of money. There is no way in
hell people are willingly working service jobs like being a watier at Siskos or a suds slinger in Bozeman at the theme park because they think it's
fun.
Ya know, unless you were allowed to tell people to go to hell in your shop without consequence.
It becomes a stage play. Don't tell me that's humanity evolved.
I weep for thy lack of love for the bard.
It is his ship. If he wants legal names she has to follow protocol. If she legally gets her name changed to Seven than that's what Shaw would call her. But as far as we all know ship protocol would be to use legal names with rank not nicknames. Shaw is a by the book guy as Terry Matalas already stated.
THE RIDE. NEVER. ENDS.
Also, probably that.
"So Commander Hansen..."
"I prefer Seven."
"...did you change your name?"
"Sir?"
"Did you change your name with the Federation records office?"
"...no. But it's my prefered designation."
"I run a very professional ship. You may have had a bit more leeway back with Admiral Janeway or Retired Admiral Picard, but I run this ship by the books, very organised and formally. Which means I'd prefer if you went by Commander Hansen in the same way I, everyone on this ship, and many officers in Starfleet, go by their last names. To explain it further, it is to instil that everyone has a job to do, and is expected to be professional at all times."
"...I understand, Sir. If I may make my objections known?"
"They're noted, as is your right."
Which yeah, makes more sense to me knowing Matalas' love of complicated characters that seem like dicks at first blush.
I can also see 100% why Shaw was such a cock at Dinner. Two people who have a frankly disasterous, rebellious records and then clearly came to come and try and steal
his fucking ship. Likely abusing their personal relationship with his XO to do so.
Which. Ya know.
They did.