The mRNA modification that I was aware of on the spike protein mRNA in the vaccine is used to enhance ribosome binding, thereby increasing its efficacy. This is not an uncommon modification in protein production. I was not aware however of all the studies of other mods that were discussed in the article you linked to. It is quite fascinating that all these effects have been linked to specific mods. It warrants further exploration.

I am not aware of any other epigenetic mods in the vaccine mRNA other than the binding enhancement. That does not mean that they don't exist. In truth, it would be an excellent place to hide a nefarious activator; however, unless there is evidence of it, I will not indulge fantasies (there are too many other more tangible avenues of research that demand attention).

I have not been able to find the exact mRNA of the vaccine (including modifications). In truth, studying it even if I were able to find it would take quite a long time. I am not an expert in epigenetics and would have to look up every detail to get a complete picture. I will keep an eye out for papers on this topic. If anything comes out I will post on it.