-Unlucky! Cumin is one of the most awesome spices! It is almost impossible to make north indian cuisine without it.
The flavour of cumin is not at all like caraway, yoiu cannot substitute the two. Caraway is more similar to fennel in taste, completely different to cumin!
You might try more south indian type cuisine using mustard seeds and curry leaves ...
I don't know if you can make it with only dal but I made a dosa with masoor dal and rice. 2 :1 ratio. Ie more dal than rice. It turned out perfect and tasted just like a normal dosa. Rest of the steps are same. I added some methi seeds to aid fermentation