Curious to how long the frozen structure can "survive". I wonder if it's a good idea to freeze one such frog and thaw it centuries later (an amphibian time-traveler!)
If kept in pristine conditions (perfectly sealed to prevent evaporation leading to dehydration, deep freeze), is there a particular chemical needed for life that we might expect to break down first?
Since chemical reactions happen in the freezer just slower...
Not possible - the oldest ice we've found on the planet is much less than 10 million years old. Even if some area remained frozen long enough to contain an intact dinosaur, it would be buried deeply enough and under enough pressure to just be a bit more arctic oil by now.