Is it permissible to pray behind a imam who dyes his hair black? 2. is vanilla essence or flavouring halal those the masala change if its suitable for vegetarians?

1. It is Mukruh Tahrimi to perform Salah Behind an Imam who dyes his Hair black, as he is a Faasiq.(Ahsanul Fatawa Vol. 3 Pg.294). You should perform salah in another Masjid, however if there isn't another masjid, then perform salah behind him, instead of on your own. In this case the sin would be on the heads on those who appointed him. If there is a possibility of them listening to you, then approach them and ask them to replace the imam.(Fatawa Rahimiyyah Vol.4 pg. 171 -Darul ishaat)

2. Yes

3. It is a synthetic alcohol used as a carrier. Sweets etc containing it, would be Halal.

4. Tasmiyyah means to name or to read Bismillah. Muneebah is a suitable name and it means a female who is repentant and turns to Allah.

And Allah Ta'ala Knows Best