I wonder if your issues comes from something else on the server as opposed to incompatibility with 3.3.9. You're not supposed to get debug errors and while they can be harmless, they can also be a significant problem.
Perhaps try running a phpBB 3.3.9 board in XAMPP on your computer: https://www.apachefriends.org/ then try using the extensions you already downloaded.
See if they break the board. I honestly think your problems are with the extensions not playing nicely with something else on your site's server as opposed to incompatibility with phpBB 3.3.9.
Also, what do you have against Americans accessing your site?