For your TJ with the 3" lift, you could easily look into replacing the fronts with YJ's and keep the rear stock. You wouldn't have to change the rear unless you change the length of the upper control arm. The flex line follows the control arm. The front stock YJs are 3" longer than the TJs due to the longer steel line at the caliper end. I replaced my TJ front brake lines with the YJs and haven't had a problem at all.
Since you live and drive in a wet and salty environment, the steel hard lines will be more the problem. Anytime you touch the rusty line, it may crack or break due to the thin wall of the tubing. Replacing these with the stainless steel will be beneficial. However, you will still have the rust problems, just not as drastic. The soft lines have steel leads.
Then also look at if the brake lines go bad, what about the steel bushing inserts, suspension nuts and bolts, and any other nut/bolt on the Jeep.
My Jeep came from OH and when I replaced my front brake lines I had to splice in new line due to the cracking. Same when I replaced the rear axle.