EU national getting into a Civil Partnership with a tier 4 Chinese national. Pre-settled status.

Hello everyone,

I am a greek EU national and have been living in the UK for 9 and a half years continuously.
While at university, I met my girlfriend two years ago, a Chinese national on tier 4 student visa, and we wanted to make it official when she finishes her masters.

I am planning on getting settled status soon and I have the proof required but I wanted to figure out the process of her staying here with me after uni before I do so.

I spoke with the home office and they said that if we have proof of relationship it is as simple of getting pre-settled status for her. Is that true? Does she just pin the relationship document, her name and my settled status application number and that's it, she can stay full rights and all?

Her visa expires mid-July, we were thinking of moving in together in April.

Can she firstly rent a house with me (right to rent immigration) as we would be required to live together before giving notice for a civil partnership?

Is it as simple as giving notice and providing all the proof, how long will this take 30 days or 70 days?
We have lots of proof of the relationship although we are not earning any money at the moment (student loans + family), we are not applying for a spousal visa (student loans).

After that, should she just make an application for pre-settled status and put my application number?
or should I wait and do my settled status application with her?

What happens if we get into a civil partnership and the settled status take longer than when her tier 4 visa expires.

I'd appreciate the help.