2nd opinion on lawyer advice: EEA FM vs RC?

i have received advice from a migration lawyer that i find dubious and want to double check with the real life knowledge out there:
- Me: Swedish citizen, living and working in the UK for last 6 months
- me and my unmarried partner have a lasting relationship +5 years and the papers to proof it
- She is an American citizen currently in the UK on a regular tourist visa that expires in the next few weeks (American can stay in the UK up to 6 months without visa i believe)

We originally planned to leave the UK very soon and apply for the EEA family permit, re-enter the UK and then submit the RC.
However, the lawyer says its not needed. Instead he says my partner doesn’t need EEA FP due to me exercising my treaty rights as a worker in the UK. So he suggest my partner apply for RC directly, without a EEM FP as she is in the UK already:

“if she applies prior to having been here for 6 months, her application will be acknowledged by the Home Office and she will continue to reside legally here until the application has been assessed, regardless of how long it takes them (it can be up to 6 months)”

is this accurate advice? i am terrified of abusing the rules and her overstaying her visa.

Also if submitting RC I will need to hand in my passport as well. Waiting for COA takes up to 1 month? I do have a 2nd passport, does anyone know if I can use that for travel, until I can request my first passport back?

Does the advice from lawyer makes any sense?
cheers

See also AB & Anor v Home Office [2012] EWHC 226 (QB) (16 February 2012), a judgment analysing unmarried partner's rights.

Thanks. One thing though...how do we know how they view unmarried partners these days and their interpretations of the rules?

101.