You can buy the car seat and use the snap and go. Its much lighter than a travel system and easy to store away.
Yes I have a jogger and have to get the adapter I saw alot for many different brands if that helps
You need to research online. Some brands of carseat will fit any stroller but you may have to buy an adopter/concerter. I personally prefer travel systems because I know it'll fit for sure and most of the time you don't have to spend extra for that concerter. So it all depends on what you like. Sometimes you may find a carseat you really like but the darn converter is very expensive or they may not even manufacture it.
Have to buy the travel system pair