小白兔,Questions about lost passport

I lost my passport few years back which has my F1 visa stamp for my first entry into US. I got the new passport later on.
For filing I-485, they need all pages of my passport,

Will this be a problem since I can only give them all pages of my new passport?
Do I need to explains this to them?

I have a Canadian PR visa stamp in my new passport, will that be a REF in the future?

Thanks!!!