would like to start using zwift...many questions

I just got started with Zwift. I got the Kickr from wahoo.

My setup is to run the app from my Mac into a monitor. Others do Apple TV into their main tv.

Not sure about the min spec needed for the computer. iPhone or iPad will work too. But a bigger screen is more immersive

Between those two trainers I'd choose the kinetic, but is there a reason you're limiting yourself to those two?

For zwift, you need two things:

1. A "headunit," either a computer with decent gaming specs, the apple TV, an IPAD, or iphone
2. A power meter or smart trainer, or a cheaper option is a kinetic fluid trainer with the kinetic inride sensor

Do you already have a power meter? Are you interested in training and racing with power?
If you want power indoors and outdoors, get a power meter. They are similarly priced to a smart trainer. Wheel-on smart trainers aren't accurate anyway.

As someone else mentioned if you're broadcasting power through ant+, you'll want an extension cord to get the usb cord and ant+ dongle right under your crankset.

I run zwift on an iPad Air and have a Kurt kinetic rock n roll trainer with the inride sensor. I also have a wahoo speed and cadence sensor. I use the Kurt kinetic sensor for power and wahoo for cadence. Works well enough for me.

If you are looking at purchasing a new trainer, I would recommend reading DC Rainmaker's trainer review. He does a great job of going through all of your options from low end to high end.

For the best experience possible, you'll want to use a direct drive smart trainer. . . but that's going to cost quite a bit of money. Personally, I think it's the way to go for both the realism and more important, ERG mode for workouts.