I find it very hard to believe this program will be up and running for Light Vehicles as of April 1, 2025.
For motorcycles the spring is a crazy time to get service of any type and the ability or willingness of dealers to allocate resources to a new and more time consuming government mandated program for private sellers will be very limited IMO. Dealers will be more focussed on supporting their own traded in stock and getting it ready for resale, not helping private sellers prepare to compete with them on the market. Assuming bike dealers will be ready at all.
For all Light Vehicles the cost of the new inspection will greatly assist dealers in leveraging unneeded or overly expensive repairs from private sellers. The inspection fee, maybe $300 - $500 has to be paid whether the vehicle passes or not. So you can expect dealers to come back to seller with a list of things that have to be done so the vehicle will pass.
Key question is if a hard copy safety inspection certification issued prior to April 1, 2025 can be used to register a vehicle after March 31, 2025. I assume so and that they would expire in 36 days. You can expect a frenzy of private sales in March and April using the old process before it expires.