Mark.... I have a 3000 which is close just one more engine.
1. Most of these combo units the gps have an internel antenna. I have one, its a garmin 431, works great. Why put up a antenna if you don't have to.
1.5 I also installed another fishfinder.I installed the transducer on the starboard side transom, in between the outdrive and trim tabs. Again works fantastic.
2. The frig..I would go with what is in there. Yes it might cost you little more, but it will be heck of alot easier for the install. You can find the norcolds most anywhere.
3.The Tv. I know most flat screen tv's are 12v then they have alittle box to handle the 110 v . So if you have a 110 plug when at the dock and a 12v plug when on the hook and somewhere inline you wire it in on the inverter.
Have fun whatever you do decide, you do have lots of options.