You can either play it early on and slowly build counters on it by attacking throughout a few turns, or you can drop it when you have an army of elves in play and trigger it with just one attack
Try protecting your Pendulum cards with Pendulum Impenetrable , or bouncing all the Number monsters back to the Extra Deck with Numeral Hunter
Once it's Special Summoned, including outside of Xyz summoning, you can either attach a banished Machine Monster to it as material or send a card an opponent controls to the Graveyard
General Idea of Frog Side Pattern Frog decks typically run little to no backrow, and the backrow they do have is generally chainable (e.g., Raigeki Break, Phoenix Wing Wind Blast, Threatening Roar, etc.)
MTG Arena doesn't attack my bank balance so much either
Once the exiled permanents return, theyre considered new objects with no relation to the objects that they were