Replacing 22 year old Autohelm ST50s

[Callisto]

One of my trusty Autohelm ST 50s (the tridata I think) is shorting out and tripping the breaker that the instruments share with my newly installed e-97 chart plotter (hybrid touch). I have isolated the instruments in the circuit and eliminated the breaker tripping. Now I think that I am faced with replacing the instruments I installed 22 years ago.
I am planning on installing an I50 tridata and an I60 wind instrument (I need two instruments in that rectangular proportion to fit my helm station).

Questions:

1. Should I pull all new wire or just replace the ends on the wire that is in place with the new plugs.

2. Will the new depth/temp transducer and the new speed transducer fit in my existing holes/threaded sockets in the hull or do I need to haul the boat and change the thru-hulls?