Just to be clear, you say they will be releasing new sensors in 18 months and putting them in H5D cameras? Will these be CMOS? And in 3 years time they'll release the H6D? And you've been privy to this information from Victor Hasselblad AB?
From Hasselblad themselves, R+D are testing new prototype sensors for the H5D. The H5D was specifically designed to take these 'new types of sensors'.
I'm assuming 'new types' means CMOS, at worst, true full sized sensors.
logically.... 2016/17 H6D
You can conclude with reasonable certainty that halfway through the product cycle they will release these new sensors priming it for the next Gen H6
Factually there is a new type of sensor(s) coming in 18 months, I've had this info from two different techs at Hasselblad. Everything else is conjecture but it fits Hasselblads revision cycle.
The sensors aren't specifically from Sony, there are multiple companies putting their designs forward for testing. No names were given.