I booted whichever onion girl had worse brave/faith, and never really used the other one, just kept sending her on jobs to build her just right. I used Rad a bit, but he spent most of his time as a monk, and Boco in Barius Valley because his ability list is named WARK! and has good water movement. It was mostly a knight with basic skill, a thief with basic skill, an oracle with white magic, and a black mage with time magic. All low levels, no super skills.
I did enjoy using Boco. A noble steed, took my knight into the thick of the battle, dropped some meteors and then ran around healing. I'm much happier having him as a special unit like this instead of generic chocobo.
I think adding some MP to the summoners at barius (maybe give them chakra!) and changing the chemists at goug into wizards, and beefing up the enemies at the gates of lionel would be good for the difficulty curve of chapter 2. The archer that spawned next to the party did nothing but miss steals the entire fight.
I never tend to use item, so do whatever you want for it. It just seems like such a bland option and I always swap it out as soon as I can. Now, if chemists can throw buffing items or debilitating items, it would be a different story. If you really want to nerf item, take away the infinite vertical usage.