1) Does flavored tea that has a good smell require birkas hareiach?
2) How is a single woman noheges regarding birkas hagomel?
1) Yes, if one smells a herbal tea with the intention of enjoying its scent, one should recite a berachah. If one takes the tea to drink it, and only smells the scent by the way, one would not make a blessing. Note that the scent of ordinary teas is not strong enough to warrant a blessing upon “enjoying the scent,” and only if the tea is truly fragrant would one recite a blessing.
The blessing that one makes would be the appropriate blessing for the herb, and hence would usually be borei isbei besamim.
2) There is no full obligation of reciting birkas hagomel (see Magen Avraham 219), and the custom of many women is not to recite birkas hagomel. However, Rav Moshe Feinstein (Orach Chaim 5:14) writes that a woman should make the berachah in front of one person; a married woman should make the berachah in front of her husband. For Sephardim, the woman should make the berachah in front of a minyan (based on Kenesses Ha-Gedolah and others).