My lawyer failed to include my employer and only included the civil service commission in appealing their decision in the art 78

Way more details are needed to properly address your inquiry.

What legal ground do I have to pursue, if any, if a co-worker spreads rumors about me to another co-worker?

Sounds like your supervisor gave you sage words of advice, both you and your co-worker should follow it. As to potential legal claims if something...

They can change it and you can quit if you don't like it. There are not any laws to my knowledge that would "protect you from any consequences" if...

II feel like they want me to work and risk hurting myself again ?

Notwithstanding whether you were paid under the table or off the books you can still file a workers compensation claim.

Is it illegal to claim you're a Military veteran to gain the sympathy of a company so that they may exchange a product?

Falsely claiming that you're a military veteran is despicable. Don't do it.

For whatever it's worth, I've procured background checks for my corporate client's on literally hundreds of employees, none of them have included...

It appears to be a legal and enforceable venue / choice of law provision, so the dispute should be resolved in Seoul.

Is It legal to use another person written instructions of how to make something?

The words and language used in the instructions likely are the creative work of the author and therefore subject to copyright law. There are...

A participant in YouTube's Content ID program is regularly making false claims on my content. Do I have any legal recourse?

Check the Terms of Use for Youtube, read a simple synopsis / treatment of the DMCA, send a letter to the parties involved identifying the issues...

My employer states I owe them money from ST DBL

You would need to review those policies in detail in order to find out the answer. Also, the FMLA may, but you should hire an attorney to research...