Welcome to the STD forum.
Congratulations on following safe sex practices, especially with high risk partners like commercial sex workers. Using condoms for genital or anal sex provides nearly complete protection against STD. Oral sex is low risk, and kissing and fingering carry no measurable risk for any STD. To the specific questions:
1,2) Your negative test result are reliable and I see no need for further testing.
3) None; see above.
4) You didn't need testing for any of the infections you mention, if this is your only potential STD exposure. All sexually active persons (outside mutually monogamous relationships) should be tested from time to time for chlamydia and gonorrhea, so you might talk to your provider about having them now if not done recently. But not because of the specific exposures you describe here.
Here is a recent threat that explains why STDs are not transmitted by the kinds of exposure you describe. Skip to the end of the thread and read my closing comment:
http://www.medhelp.org/posts/show/1119533
Bottom line: No worries. Best wishes--
HHH, MD