Yes, you can transfer your mutual funds to Coin. Process explained here.
Demat MF’s are those which are stored in Demat form. MF’s purchased directly from the AMC need not be in the Demat form, it could be in the form of an MF certificate as well. These funds in paper form have to be redeemed directly with the respective AMC itself while in paper form.
Yes, you can have all your MF units transferred to Coin under the same folio number.