and to answer your original question, it should be okay however its definitely more expensive. You also have the choice of booking 3A end-to-end in 14660 itself where 3 seats are available and the 4th will surely confirm.
And if you still want to go with your option to have 2A for JU - DLI leg, then you can book on IRCTC and then submit a written application on the PRS for changing boarding point from BANE to JU although that's probably not required at all. But you can do that for peace of mind.