I received the exact opposite response from the MR call center. I was told that there will be one time points conversion, and grandfather to Platinum Premier, on August 1st, if you have met the threshold for Lifetime Platinum in the Marriott program. Going forward you can still qualify for lifetime platinum in the new program using the old qualifications but it will only map to the lifetime tiers in the new program. The grand fathering to LTPP will be a one time event.
Unfortunately, this seems to make sense as there has been no mention of two points conversions.