1) What is my risk of catching a STD by licking her vigana from the outside a couple of times?
In theory, if she had any sores, you could get syphilis. If she didn't, and you would have mentioned it if she did, you didn't have any risk.
It would take more than a couple of licks to become infected with anything.
2) What is my risk of catching a STD with rough Genital to genital grinding altough I had underwear on but she didn’t and fluid were seen on my underwear after.
None at all. STDs don't go through clothing, even if your underwear becomes wet with fluids.
You really have nothing to worry about here.