Pretty sure you can select DX mode on my D750 to use the 35mm. I would assume the D610 would be the same. But 35 mm on a crop sensor is a 52.5mm so why would you bother? Sell or trade the 35mm towards that 85mm IMO.
Why pay the big $$$ for the full frame FX sensor then only use it in DX mode? Buy the DX size body if you are going to continue using DX lenses.
Doing video with an SLR is a commitment to using more professional technique. For example the autofocus motors in the lens makes a lo of noise the microphone WILL pick up. Either turn off AF is get an external microphone and or audio recorder. SLRs can work for serious video but are not the best for casual use. For that get a $250 video camera.