Thanks for the questions.
1. BG does not want us to "translate or transliterate"; only transcribe in the the data fields in the character set and language on the stone.
2. Can you transcribe in both Hebrew and Russian character sets? If you can and have both character sets in your computer system use them both.
3. BG has never given a clear indication that what I am about to say is OK with them, but I don't recall any previous discussion that would clarify. What I would do is to transcribe the person as if there were two people. Do one record first in the primary language (English/Russian etc.) and then open another iindividual record to transcribe in Hebrew or other language.
4. If you can give an English or other Latin language version, please put that in the Notes area.
5. If the stone gives the father's name, that should go in the "Not Buried Here" section.
Don't worry about those language filters. They are a mess. I noticed they have recently made some changes to the language list, but not sure why they did what they did. If you happen on a stone you can't or don't want to transcribe and can correct the language, please do so. I don't go looking for them, but then I am only fluent in English (lightly read a few a others but not fluent enought to transcribe.)