Question

Does dupe frog or poison draw frog miss timing if you tribute it with substitoad?

Answer 1

Poison Draw Frog will miss its timing because it was sent as a cost and the last thing to happen is Substitoad's resolution and not Poison Draw Frog being sent to the graveyard.
2. correct. see above
3. correct. the last thing to happen is Poison Draw Frog being sent to the graveyard. so the timing is correct to trigger its effect.

Answer 2

Explanation:

yes dupe frog or poison draw frog miss timing if you tribute it with substitoad.