Eating Lunch at a Yeshiva
Q: If I visit a Yeshiva to learn a little and hear a class, is it permissible for me to eat lunch there even though I am not a student there?
A: You have to ask one of the Rabbis there. I do not have the authority to decide for them.
Lending an Electronic Object to Someone who does not Observe Shabbat
Q: Is it permissible for me to lend an electronic object to someone who does not observe Shabbat?
A: In general, yes. But it is forbidden if it is on Shabbat itself or if on a weekday the person explicitly says that he will use it on Shabbat. Mishnah Berurah 347:7.
Q: If one promises something but says "Bli Neder" (without taking an oath), is he obligated to fulfill it?
A: One is certainly obligated to fulfill his promises even if he says "Bli Neder". If one says "Bli Neder" and does not fulfill his promise he has not transgressed the prohibition of an unfulfilled oath, but he has still transgressed towards his friend (A groom once continuously bugged the Chazon Ish to attend his wedding, but the Chazon Ish refused. The groom suggested: Ha-Rav can say he is coming "Bli Neder". The Chazon Ish was shocked:"Bli Neder" is still a serious acceptance, it is not something meant lightly. If I say it, I will be obligated to attend).
Tzedakah or Kaddish
Q: Is it preferable to pay people to come to my relative's grave on the Yahrzeit so that I can recite Kaddish or to donate the money to Tzedakah?
A: Tzedakah, since giving Tzedakah is a clear Mitzvah, and there is no Mitzvah to recite Kaddish by a relative's grave.
Q: Is it permissible for me to attend the wedding of a Druze friend with a Druze woman? The wedding will not be Kosher but they will provide Kosher food for the Jewish guests?
A: Yes, since the wedding and meal is permissible for them. And "Maarit Ayin" only applies to what our Sages decreed.
Talit for Single Man
Q: Should a single man wear a Talit?
A: There are various customs among Ashkenazi Jews. Be'er Heitev 17:4. Mishnah Berurah Ibid. #10. But he should certainly wear Tzitzit. The Sefardi custom is for single men to wear a Talit. Kaf Ha-Chaim 8:12.