Fiance visa EU and Non EU citizens

Hello to everyone.
Here I am hoping to share some experience and get your opinion and advices.

I am non EU and my future husband is EU citizen living and working in the UK.
After my partner proposed me in Summer, we checked all visa types and decided to apply for Settlement Marriage (Fiance visa, not spouse). It seemed better for us to wait 2 months before the wedding than after it. Therefore, we are planning our marriage in the UK this winter.
It has been 15 working days since I received an email from Sheffield (application is being prepared for consideration by an entry clearance - 1) by the way, should we start counting days from this point?).
We have also bought priority service.

My doubt is that my future husband does not hold a resident certificate, but he works officially for more than 6 months (the salary is higher than 18600) and the rent of our apartment is on his name. In this case, 2) can he be considered as settled in the UK? How strict is it? I have read that EU citizens actually do not need this certificate to be settled, but in our case he is my sponsor.
The other documents should be okay. We have been together for 2 years (more than half a year living together in his country and in the UK on base of my student visa - it is worth pointing out that I did not hide our relationship when apply for the previous visa, even sent some pictures to show our intention to live together). Neither of us had been married, we have no children or other depended relatives. Many holidays were spend together with parents etc.

Moreover, wanted to ask based on your experience, 3) how much time will our application take? So stressed...
Will be waiting for your opinions.
Thank you very much in advance...