The application process for pilots is similar to other services. USCG flying jobs are in relatively high demand (due to lack of deployments and the feel-good factor of saving, vice killing, people), so they are able to attract some pilots from other services.

The training is actually navy pilot training.

You cannot pre-select helos or fixed wing. The ANG/USAFR is the only branch which allows that. You will be randomly assigned an aircraft, and it will probably be a helo since that is what the CG flies mostly.

I do not think they have a flight-guarantee program...I think you have to join the CG and complete OCS before getting assigned to flight training, and there are no guarantees.