Black Mamba

I just purchased xp10 and just joined this website. I have been away from simming for a year and I am starting to reengage. Can I use any or all of the addons from FSX such as planes and scenery that I downloaded from other manufactures i.e. Aerosoft, Iris, Lotus or REX in XP-10 and will they fly? Also, on average how long does it take to load XP-10?