Just a thought here but
Do you realize that you'll have to do the CFII as well if you intend to train people for their instrument rating?
Maybe you already have enough hours to unfreeze it for that purpose, I don't know. You don't really give any information as to how many hours you have as an instructor, that could be helpful.
About the visa, you can apply I believe for a J-1 and work with that.
On the other hand you could maybe get an M-1 which is what a freind of mine did, he was still short on a few hours so he applied for it and got it. Now this is a bit unorthodox since the M-1 is intended for students that are actually in training.
I don't know of any other visas that you can apply for.
Cheers mate.
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