These appear to be lead inserts to adjust the swingweight, I am not aware of any other objects Titleist uses in their shafts. They should not be necessary for your new shafts unless you need to adjust swingweighting.

That little piece is a brass weight used to properly swing weight your club. When they say its a D2 or D1, that's how they get to that weight with shafts and grips that weigh differing amounts. You'll discover that almost every one of your clubs has a brass weight at the end of differing lengths/weights to achieve a constant swing weight throughout your set.

That is a lead tip weight. You will absolutely need them when you reshaft.

I do all of my own club work so you need to know what you are doing.

You need to account for the new shaft weight, grip weight, ferrule weight, how many layers of grip tape you will use and even how much epoxy you use.

There is a lot to consider when reshafting. It's not just glue and cut.