You can't use different emails for different IFW's if it's across the same freebie network. IFW refers to a single Incentive Freebie Website. Most networks are made up of multiple IFWs. If you use a different email address within a network, you will be put on hold because it appears as though it is an attempt to set up multiple accounts which is not allowed. Most freebie networks have an option to extend your existing account from one site to the next within their network and that keeps your info consistent and helps speed up the registration process. Use that anytime it is available..
It makes trading & life a lot easier just to use one email address for trading. I have personally been using the same email address for all of my freebie trading as well as my PayPal account since 2006 and I've never had any problems at all. The main thing about the PayPal account security is to keep a unique password just for that account and change it occasionally if you have concerns.
Simple variations in your name won't matter as long as it matches what is on your ID or driver license closely enough, in case you ever need to provide ID verification. Your physical address has to match, too.
Make sure that whatever email address you enter into the Trade Manager for a trade matches up with the email address you actually use to sign up through your trade partner's referral link & that you put in the correct PayPal email address so you can get paid.