Michelle,

Welcome to the RV Dreams forums.  You have certainly found a good place for asking questions about the RV lifestyle.  So, feel free to ask questions.

As for the fuel additives, I think the products like Sta-Bil are primarily for use when your gas cans or engines will be idle over a long period of time.  If you would be using your generator regularly to where you are always putting in fresh gasoline, I don't think you need to worry about that.  Some of the other products you mentioned, I know nothing about.  As far as the octane booster, I would think that if you are getting an equivalent octane gas in Mexico as you would in the states, it wouldn't be needed.  However, if their octane ratings are considerably lower, it might be a good idea.  Most of the engines are engineered to run on something like 87 octane (or equivalent).

Now, having said all that, I'm hoping someone will come along and give you answers based on knowledge from actual use of the products.

Good luck.

Terry