Your language is fine, so no worries. :)
So, my questions are:-
1- What are the dangers of her rubbing her vagina/clit on my penis? "grinding naked"
It is possible that you could get herpes, HPV or syphilis from this. It depends on how much grinding there is, and how long, but if it's heavy grinding or rubbing, this could be possible. These are more likely to be transmitted by actual penetration, but it could happen.
2- Can I get infected with any type of STDs or STIs from fingering her?
4- Would I be at risk of anything from having an unprotected handjob from her?
I'm grouping these together because there is never a risk from fingering, handjobs, mutual masturbation (where you're using your hands on each other, and possibly on yourself again). I'm going to include more info at the end of this that helps explain this more.
3- Would I be at risk of anything from having an unprotected blowjob from her?
Yes, you can get gonorrhea, chlamydia, NSU (a non-specific infection in your urethra), genital herpes type 1 (ghsv1), and syphilis from receiving oral sex. The chances are lower than with penis in vagina (PIV) sex, but it can still happen. If you are getting oral sex from a sex worker, you should definitely use a condom for this. Condoms don't offer full protection - you can still get syphilis and ghsv1, but the chances will be much lower.
Syphilis is uncommon in most developed countries, but it is still a risk.
Here are some posts from our experts (when we had them) that may help about the transmission using hands -
- read this thread thoroughly. There is an excellent explanation about why certain activities are not risks, and why others are.
Hope this helps!