pale blue
Never. The only person in ivory should be the bride. It is inappropriate for a person at a wedding, mother or not, to wear the same color as the bride.
Since it is the bride's mother who is sending out the invitations, which is customary then the return address should be to your parents or your mother.
The future bride and groom should have to make arrangements for the both of them to get together, like dinner or something like that.
Saree
The Mother of the Bride CAN wear black---but it would be very poor form. People at weddings should be wary of black.
How to toast the mother of a bride
seaweed green
The mother of the bride is suppose to proudly represent her daughter on her special wedding day. It should never be a problem for the mother of the bride to buy a dress suited for the wedding. Some wedding shops or rental wedding shops will rent out dresses for the mother of the bride which would cost less.
Being that we are in the 21st Century he can do either or he can take them both down the isle. Tradition would have been the REAL mother of the bride, not the step-mother. You discuss it with the father. He should have an input into this matter.
the mother of the bride should wear red because it color coordinates well.
A wedding toast to the bride's mother is sometimes made by the bride. She will thank her mother for all she has done for her.
Only if the bride wants her there.