So my main quad has once again developed an issue on the receiver side.  The FC is a Crazybee V3.1 12A D8 with Diversity. 

So I had an issue with it recently and had to strip it down for re soldering.  After reassembly I am getting failsafes at about 50 m, but only when the quad is looking at me.  The antennas it uses are basically pieces of wire with a ufl on the end.  I don't have any to replace them with.  But what I do have is a pack of dipole antennas for elrs.  Could I use two of those antennas and mount them front and rear?

In case someone asks, no I can't change it to elrs.  During a crash I destroyed the usb socket on the FC, so this quad flies like it does now with no chance of changing any BF settings.

Yup, you should be fine. Both ELRS and d8 are tuned to 2.4ghz (assuming those antennas came from a 2.4ghz ELRS rx, not a 900mhz rx).

Double check that the u.fl jacks/plugs are actually the same size though. I vaguely recall some FrSky receivers using a non standard u.fl size.