I had a 04 PT175 and put a Terrova 55#/12v on it with a grp 27 TM battery and could long line all day long up to 1.5mph. I also had a HB 788 ci HD on the front with a HDS 8 w/SS at console hooked to cranking battery, never had a starting issue with the Merc 60 2s. You don't need the 24v unless you want to pull CB's. Do you have a below deck storage compartment up front near the seat post, should be room for 2 TM batteries there but probably not in transom area, plus boat will be more "butt" heavy with another battery.
The IP can record up to 6 tracks, so no real need for the Ilink unless you just want it, but all of this will cost more $$, but it is your $$.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.