I have a 4" lift that came with shocks, coils, bump stops, rear trackbar bracket, sway bar links. It did not come with control arms or a front trackbar bracket. So right now my axle is off centered and my caster is off. So I was thinking to start with a drag link flip kit and get some control arms

 

How much actual lift do you currently have? A raised front track bar bracket isn't going to center your axle without an adjustable track bar. It might get it closer than it is, but it won't be prefect.

 

As was mentioned in your other thread - find out what the components actually do, and what considerations there are, before arbitrarily throwing money at it. My suggestion would be to add the caster correction and drive it to see what 'you' think of the handling. And then decide if you want the flip.

I drove a 4" lift for several years before finally getting around to adding the front/rear raised brackets and flipping the drag link.

 

To adjust caster is adjustable control arms correct? If I read other posts right

 

Yes front lower adjustable control arms will allow you to adjust caster. We typically recommend both front upper and lowers because you will be able to fine tune your caster and pinion angles to get the Jeep to drive as best as possible.

 

Cam bolts, drop brackets, longer/shorter 'fixed' arms, adjustable arms. They will all change your current caster, but there are positives/negatives involved.

If you go with adjustables, either upper or lower will work. Uppers will be adjusted shorter than stock to lower the pinion and raise the caster. Lowers will be adjusted longer than stock to do the same thing. Uppers should be a bit cheaper, lowers will likely give a better range of adjustability. As noted, getting both sets allows more fine tuning, and adds the ability to reposition the entire axle forward/backward in the wheel well.