Is the exesiting breaker panel treated as a sub feed panel with neutral bar un bonded and neutrals separated from grounds. Grounds being bonded to panel.

You'll have to do a bit better explaining this.

Are you using a main transfer switch? Transfer panel?
Is it a service rated switch?

Also, please try to use punctuation and capitalization. Posts are very hard to read when written in texting speak.

I am using a 200# service rated Generac nexis smart switch. Question #2 I am running 7 control wires from generater to smart switch in conduit. What type of wire should I use. Run is 75 feet.

In this case the existing main panel would now be treated like a sub-panel. The grounds and neutrals must be separated with the neutral isolated from the panel box.

For the controls I use #14THHN/THWN. They are not carrying an appreciable load.