I think folks have covered things nicely for you. I've still got the ball handle on my 550 and it works just fine. Likewise don't have the strong mount and been using my 550b for a LONG time. Extra powder measures are nice, but hardly necessary. I use a high capacity cat feeder for my case bin, keeps the cases convienant and only a few are in the bowl at any time. Bullet tray? I just set the bullets in their box right beside the press and it works fine for me.
Lee dies work just great. If your press is off enough for tolerance stacking to bite you, it's time for the press to go back to Dillon.
I'd maybe cull that list down based on the advice you've gotten and call someone else.
550B is a fine choice, I've loaded a LOT of ammo on mine.