How do I keep track of them any hints or tips?

They always seem to be wandering off.... and I can't find them to assign them or keep track of who I already assigned to what..

Is there a way to see your trade routes and which settler is assigned to it..

or rename the settlers?

One guy I assigned to a guard station never seems to be there...

I haven't gotten up high enough to build stores, but how do these work?

You can build a bell which makes all character assemble around it.

But yeah, managing settlers can be annoying.

The assigned guard patrols the settlement so as long as it is assigned, you are fine.

You just build a store and assign a worker to it... though in my case, the Lv.1 weapon store is bugged in a way that the merchant is never standing at it.

Move it a bit and reassing him

Tried, doesn't work and the problem persists in multiple settlements with only this shop. I must build Lv.2 shops for it to work properly... not that this is much of a problem now that I have extra caps.

Fortunately, other shops work as they need to.