Nautilus E614 Elliptical

Adapter. The adapter plugs in at the base of the elliptical. The wiring for the board runs through the frame. Easy to hook up.

Doesn't come with the strap, and I'm unaware of what a Polar strap is. It does have built in handles with sensors to detect heart rate, which so far works well for us.

I'd say no - it operates very smoothly, with little vibration, but the machine is very heavy and probably would leave indentations in the carpet.

No. They are some what wide pedals allowing you to move your feet in our out as needed a few inches.

There are 2 user profiles on the Nautilus E614. If you want to track on the app, each user will need your own app and you need to sync the correct user number to the correct persons app.

It calculates calories burned by the speed and settings you are using. You can put in your weight but I don't think it really makes a difference.