Hey Denver Dan,

"the only way to earn interest is to enroll in the retirement plan at either a 5y,10y, 15y or 20y plan?"
The retirement bonus balance is currently depleted:
"we provided incentives for getting involved and saving DNotes, including a 1,000,000 DNotes bonus to be paid to retirement accounts as bonus interest.

And so far, it’s been an incredible success story for everyone involved. The retirement program was so successful that the bonus balance was depleted well ahead of the intended target of 5 years."

"There's no interest accrual by just storing your DNotes in the vault?"
That is correct.

"When DNotes 2.0 is launched, this will change by not having to enroll in CRISP, but just to HODL in the vault?"
Not just in the DNotesVault, but it could be in your own wallet.
What happens to those CRISPs when DNotes 2.0 launches? There’s good news on that front! Because our CRISP programs have become such a popular feature for DNotes stakeholders, we have decided to expand its benefits. The future of CRISP will feature automatic blockchain distributions, made in two ways: 0.166% after 30 days and 4% after 365 days.

Best of all, DNotes stakeholders won’t have to do anything new to earn those distributions. They only need to maintain their DNotes at the DNotesVault or in their own secure wallet - and hold them for the designated period required to receive interest payments. That’s it! No special terms or difficult requirements to meet; they simply need to hold their DNotes to earn interest!

"Then additionally, we'll be able to stake our coins from the same vault account?"
Once deferred / cold staking is available, which may not be available for the first release of DNotes 2.0.