[HGSS] Possible to rename Rival ? + Question about OT Name

[j2k15]

Hi,

I restarted playing HeartGold.

Bad habit from Gen 1 and 2, I named myself in the game GOLD with caps and my rival SILVER with caps.

I know it's possible to rename the hero's name using PokeGen as well as DO name of all the beasts I caught.

I would like to keep those names but with only the first letter as cap.

My first question is : Is it also possible to rename rival caracter ?

Second question : If I change OT Name of all the Pokemons I got, would their curent PID still be valid ? E.g. nature has impact on PID. I guess OT Name doesn't since PokeGen let you edit this field but I wanted to be sure.