Some replies to the above stuff as wifey and I have been churning for 2 years now. The chase business cards do not count to 5/24. Do not always be drawn in by the large point bonuses as they aren't created equal, for example: 60K Hyatt points will go wayyyyy further than 100K Hilton points. Hilton points are trash. The southwest companion pass is a sweet gig, last October they increased the bonus to where if you signed up for two of them, you got the 110K points. We got the companion case in January of 2018, so wifey flies for free until 12/31/19.
The reason people apply for Chase cards first is that Chase will stop approving you for cards if you have received five new cards in the last 24 months (5/24). Amex cards, American Airlines cards and several others are normally saved until after 5/24 so you still have cards to sign up for. Since 6/16 we have 2x CSP at 50K, 2x CSR at 100K, 2x chase ink a 80K, 2 x SW cards at 60K (same person for companion pass), 2 x Marriot at 100K, 1 x Hyatt at 60K will also be next card to total 2.