hey RadheRade,
I was hoping that you would receive replies to your answers about Meldi Mata as I wish to know more about her too. But since no one has replied I will share with you the very little I know. I am not entirely sure about this legend but here it is;
A demon (not sure of his name) harassed the gods, who sought help from Devi. Devi fought with this demon to rid him of the world. However, the demon hid in a gutter/sewer to try and escape from Maa. Since Devi is ‘pure’ she could not access the ‘impure’ sewer. So to overcome this, Saraswati devi, Lakshmi devi and Kali washed their bodies to extract ‘mel’ (which is the dirt that comes off your body when you wash) and with that they formed another Devi and she was named Meldi maa (her name obviously corresponding to her creation). Since she was created from ‘mel’ she was able to access the sewers and killed the demon. As this devi was made from ‘mel’ she was also considered ‘impure’, so she was washed in the Ganges water which then made her fit for worship.
I must repeat that I am not sure the above is the right legend so if anyone knows anything different please inform me!