I didn't expect Carthy to be at the Tour and thought Clarke would ride for sure. In general, I was more in line with your prediction of:
Martinez, Higuita, Uran, Woods, Kangert, Bettiol, Clarke, Keukeleire
Yeah, that what felt like making the most sence to me at the time but with hindsight the actual roster makes sense to me.
As I said, I wouldn't take Van Garderen but I'm not surprised he's taken. The biggest American name in the team. The same way Phinney was getting selected a few years ago even though his form was far from great and usefulness for the team was rather limited at the time. I assume he's taken the spot I suspected would have gone to Woods but Woods was my biggest question mark and I can definetely see they would not deem him ready to ride TdF so shortly after such a serious injury. I'm not happy with Van Garderen but I'm not surprised either.
Clarke is Uran's favourite domestique but since Uran no longer appears to be the biggest hope of the team, his omission is not that surprising. I think Keukeleire was brought to the team to fill the role of a "guardian" for Martinez and Bettiol can fill kind of a similar role to Clarke as someone who combines rouleur and hills/medium mountains skills and he is a much bigger name ATM. I assume his place has gone to Carthy, who is potentially clearly a better climber in high mountains so I can see the logic here. Maybe they also think Clarke will be better used as a leader in some other races.
Powless at the moment appears to be around as good as Kangert. I thought they would go with Kangert for the experience but Powless is a good choice too and since Kangert is leaving and Powless has a contract for 2021, it makes sense that they would like to award Powless with a TdF debut to boost his morale.
Carthy was meant to lead at the Giro and was way out of form at the Dauphine - not sure why he's been selected. Kangert should have gone instead imo.
Carthy was clearly better than Kangert on stage 1 and 5 of the Dauphine. While, similarly to you, I kind of saw him as a Giro leader rather than a TdF domestique, maybe he just wanted to be part of the TdF team after the calendar reshuffle.
The EF guys were a little bit underraced coming to Dauphine, maybe riders like Carthy will do better at the Tour with more mileage in their legs now.