agree with you & i'm against them 'swimming'.
with your new girl its just a thought ... but have you had her checked for skin conditions? Mites in particular? often when they really don't like being touched its because of a problem, does her skin look the right colour? eg pale under light hair & dark under dark hair or red &damaged (scratches/bites/wounds, etc)?
they can often succumb to illnesses after the stresses of moving owners/housing.
However if she is only young not used to being handled much she will be very skittish, she wont have learnt to trust you (being a prey animal she's wired up to run, until she's settled).
i expect the other girls will accept her being a baby & give her a few motherly nips, or chuntering telling's off until she conforms to the current hierarchy.
i recently lost my old girl Ellie (8yrs) & was given two new furballs (under 2yrs, but not sure by how much...more like a year i think)
they were completely nuts, they zoomed around like mini rockets, i have now had them about 7 weeks, they eat from my hand, display some fabulous chooken legs & even Dopple does a front paw chillout & they will nearly doze off on my lap at cuddle time. however they still have a squealing, zoomie time occasionally when i try to pick them up.
Grace (4yrs ish) just stands & rumblestruts at them if either of them is in the tube she wants to be in, until they move! (or she just crashes on in!)
last night Orca just sat in the pipe& shrieked at Grace until she walked off, they all love to cuddle up together at lap time though.
would you be able to keep her say a month to see if she's settling in & only rehome her if things become really heated between them?
i bet she's so excited to get a loving, caring home with space to exercise & company it would be a shame to rehome her if its a few dominance issues that may settle.
good luck with her... any photo's?
xx