For the second one; instead of exploding the block, go in as if you're editing the dynamic block, set the visibility state to that which you desire and copyclip the objects viewed, then paste it into the drawing. Of course, this won't answer the fact that if you have modifications, they may not be recorded, as you will be copying the original objects. Of course, you could always use ncopy from express tools, but I wouldn't necessarily recommend that, since that only works with one nested object at a time.
Better yet, you could do as posted above, but a bit differently. Try erasing all unnecessary visibility states, saving it as a differently named block, then bursting it. Don't know if it will work but it could be worth a try.
