Hello @
pixelrogue, welcome to FT. Your questions are broad and need to address exactly what you want in a credit card to give you the best input. Many of your questions can be answered in the Wiki here at the top of the thread, such as which cards are subject to the 5/24 rule. There are threads for each of the cards you asked about, debating the nuances of the cards and their perks. Did you have a chance to look? The individual threads would be the best place to begin as you decide which from a wide array of cards would be best for you.
Generally speaking, UR earning cards are the most versatile, because the points transfer to so many programs. Avios earning cards such as the BA/Air LIngus and Iberia cards are especially useful for short haul travel because the redemptions are distance based, not zone based. The Southwest companion pass is widely considered one of the perks available. The IHG card has recently been revamped, currently has a huge sign up offer, and only you can decide if it fits your needs.