How large is the startup? I would ask yourselves if those things are really necessary? You may spend a ton of time trying to come up with a training plan, only to find it was flawed, you lose interns, etc.
I would think something more informal and flexible would make sense for your first go-round. If you've got the resources/money then by all means go for it, but most large companies haven't even figured out how to do this well.
Also guessing that if you put your best people in charge of training/coaching mentoring the interns in this formal program, they won't be developing/marketing themselves. Could end up being costly. Sit them next to your best people and start giving them tasks. Trial by fire baby!
I just think it's a little resource heavy for an early stage startup. Everyone should be contributing to the product. Especially if this is a temporary intern situation.
If you're a more seasoned startup, then ignore my answer :) You can ignore it anyway since it's only one mans opinion - but I would focus my efforts in areas closer to shipping the product.