sign_np VS pkg2zip

Would this work do you think? I haven't tried it yet but it seems to do what is needed for this to work.

You can, but why would you want to? I'd recommend just using the PSN copies of games and run them with npdrm_free. They're often even smaller than CSOs but will run as well as an ISO. Converting an ISO to EBOOT won't have those same space savings. (At least that was the case when I did it to test a while ago)

Maybe this? https://github.com/swarzesherz/sign_np

Had to update to this fork of pkg2zip https://github.com/lusid1/pkg2zip/tree/master to get the -x -p {pkgFile} "{zRifKey}" parameters to work

You download the PKG file from the game you want from the website, then you drag the PKG file into pkg2zip, you will get a folder, you need copy to copy this folder into the "PSM" folder on ux0 on your Vita (create one if you don't already have one), you will also need to get ShaRKBR33D and PSM Manager, they're both very simple to use, you open them, press "x" and they'll do the job for you iirc. ShaRKBR33D downloads and activates the PSM Runtime 2.1 package, in case you don't already have it (however you likely do because it is needed for running a good amount of game ports but, just in case you don't, here it is) and, PSM Manager creates a fake license to make it possible to boot into the games.

pkg2zip: https://github.com/lusid1/pkg2zip/releases/tag/2.3

Decrypts .pkg file using pkg2zip by lusid1

The games i tried moving to my "app" folder in ux0: were downloaded directly through nopaystation.com and converted to zip with pkg2zip then unzipped into my app folder.

Process them with pkg2zip.

Update to the latest, forked, version of pkg2zip: https://github.com/lusid1/pkg2zip which doesn't show up on Google :-)