Case2 --One default router & Two network prefix--

At first

This is the case of "source address Dyna1 use can NOT pass default router of Power1". If Power1 choose Power2 as a default router, Dyna1 MUST choose 2001:200:0:8410:208:dff:fe76:f414 as the source address.
But Dyna1 choose source address at random.
So if Dyna1 can NOT connect at the probability of 1/2.

This problem can not solve by existing implementation.
The structure which Dyna1 can know default router of Power1 is required.

Source address Dyna1 use can NOT pass default router of Power1