Yes I used mine in the dewalt xr multi tool you just have to use the screw in adapter instead of the built in spring holder.
Not the ones they gave me (although they are supposed to be Bi-Metal)
This is a pack of three and at 40 dollars for three youd be looking upwards of 120 if they did sell a 10 pack.
The OSC114JF-3 Oscillating Blade has OIS interface. If your Dremel MM50 accepts this interface, then it will work. For further assistance, contact us at 1-877-BOSCH99 (1-877-267-2499) from Mon-Fri 7A-7P CST.