Will i be able to Install SMF on my sites? And if i can, will i have any issues with safety features getting in the way of me installing packages, themes or emailing my users?

You can install SMF.

You may experience issues with installing mods/themes; usually, they have to be installed manually.

You will not be able to email your users unless you pay to have php mail enabled on your account. This is a one-time fee of $10 - join the live chat for more information.