Thanks for the reply boss,
I downloaded them all through curseforge's website, I originally had them downloaded through Twitch's modpack feature, it's basically FTB ultimate reloaded but with some extra mods I put in. I had first just went to the instances folder in the Twitch Minecraft directory, and just transferred all the mods in that folder to my server and it actually had a different error and my server host told me to re-download the mods and try again. So I went and downloaded each and every mod by itself from the curseforge website. I also attached a screenshot of each mod I had downloaded one-by-one, just so you can see it's not from Twitch and that they are in fact .JAR files.
Now that you mention the possible download issue, you may be on to something, I am using Vivaldi as my browser and it has some weird virus protection thing and I have had problems with .exe and .jar files in the past. I can try using Chrome and see if that maybe works?
Here are the links to two of the debug logs found in my folder (Not sure which one you would like to see. The last debug file was too large for a paste, I uploaded it below.)
https://pastebin.com/C5Tjtiug
https://pastebin.com/NE9QhLAj
Thanks again for the help mate
latest.log
EDIT: I removed all of the mods in my client's mod folder, then I just added EnderIO and EnderCore and it is working fine. So on client-side the JAR files are working fine.