3godzilla3 | How to Play Sonic Origins RIGHT NOW...Sort of - Sonic Classics PC Tutorial @3godzilla3 | Uploaded 2 years ago | Updated 5 hours ago
Bear in mind, this is solely my opinion and I'll probably end up buying Origins when it releases anyway, so no hate comments. 😅

Also, to play 1, 2, and CD in fullscreen, there's a "settings" file in the folder for each where you can change the "Fullscreen" option to "true". Once you save that change, the game will boot up fullscreen.

Here are the links for what you need:

Sonic 1 Forever & Sonic 2 Absolute
teamforeveronline.wixsite.com/home

Sonic CD Decomp Tutorial (tried it myself off-screen, works beautifully)
youtube.com/watch?v=poA3Ui7VYKs

Sonic 3 A.I.R.
sonic3air.org

How to extract the APK files from the Android versions (only watch until the 2:05 minute mark)
youtube.com/watch?v=QekdEBOWX7Y&t=367s