False. The setup cartridges counted for me as they were "Instant Ink Ready". I then thought I should have used them up first before enrolling but if you're doing the 300 page trial: honestly there is barely anything in the setup cartridges (I got like maybe 35 4x6" photos before colour ran out) and then once I got the big carts I never made the 300 page mark anyways (printed like mad at the end and got to 200 lol).
Yes, don't register until you're finished the set up cartridges. I set up a relative with the 3833, and did exactly that. The setup cartridges barely have anything in them anyways. I think we got through like 20 4x6" photos before colour was out lol. Then signed up for Instant Ink. Big ink carts came in the mail 1 week later. They barely print anything so the free plan will be great for them.