RED update thoughts and feedback

So I have to ask a few questions
1.) I know Grosso and Livyatan have seperate versions with MUCH higher hp, has anyone encountered said versions thus far? If so what trade route have you encountered them on (Its probably safe to assume they have much higher chances to drop the items)

2.) Whats the general consensus on the drop rate of the weaker ones anyway, somewhat rare, or in the middle? I've heard of people either getting them really often, or not getting them at all so im curious.

Edit: if what everyone has been saying about the boss not being affected by drop rate is true; that would be very interesting