Is it permissible for a woman to visit the doctor while in her `Iddah(waiting period)?
It is permissible for her to do that during day time, but it is impermissible for her to go out at night except for a sound reason.
Is it permissible to listen to chants praising the Prophet if accompanied by musical instruments?
If singing, or chanting in praise of the Prophet was accompanied by a forbidden musical instrument, then it is forbidden.
Is it permissible for a husband to sell his wife`s jewelry if he was in a hard up?
A woman`s jewelry and dowry are her own property, and it is forbidden for the husband to take either without obtaining her approval. However, it is desirable for the wife to support her husband through considering her jewelry a sort of documented debt on him.
Is it permissible for a woman to wear colored lenses?
All Perfect Praise is due to Allah, The Lord of The Worlds.
Wearing colored lenses for treatment is permissible, and wearing them as an adornment is also permissible, provided that she isn`t seen while having them on by non-Mahrams (Marriageable men). And Alalh Knows Best.