Agreed.
No matter how you go about it, if you wash you will have to deal with the water content.
Never grind for washing. If the bud is dried a 30 minute presoak to rehydrate the bud is all you need. If it’s fresh frozen no presoak is required. If you grind you are going to expose more contaminants.
Just take a pointy pair of scissors and snip the stem to pop them into quarter to half-dollar sized chunks.
Fresh frozen should be done early after the harvest. I dry half the time (5-7 days) before I buck and bag the buds for the freezer. At this point there’s no real use since you’ll need to presoak dried buds anyways. (I mean you could freeze the bud before you wash, but your bud shouldn’t be affecting the water temp that much anyways, so it’s going to get nice and cold no matter what.)
I think the issue here is you’re trying to combine two different methods of the same process, thinking you’ll get better results. That’s not going to be the case here, unfortunately.
Sure, you could run dry ice hash and then wash it to separate it but then all you’re doing is introducing another problem (the water). I don’t even know how’d you’d use dry ice after you made bubble, that just sounds like a mess and a waste of hash.
I think you need to just pick a method and stick with it, you’ll be happy either way. 
You can see my full bubble hash setup including cold-room for processing here…