Those are all separate banks, I'd apply for all three at the same time.

If you're really concerned, apply for them in order of preference with 30 seconds in between, but I doubt it'll matter.

Not sure I agree to sit on the SPG; even though the offer isn't great, I've yet to read of a really good offer on that card, simply because it's so good and they know it. They probably have no need to provide an incentive to potential new customers... (even though they are providing the 25,000 bonus right now, 30,000 with a referral)

Plus, if you want to put your spend on the best possible card, it probably makes sense to get that card ASAP so you can get the 1.25 per $; there is an opportunity cost there.