1. Hinoka has exposed thighs, and is a mounted unit just like Camilla. While one is clearly more fanservice oriented than the other, it doesn't seem like the exposed thighs alone are bothering you, based on your statement.
2. Rinka is less clothed overall than either of the female characters you don't like. But wait, she has pants. Clearly her chest bandages and pants are suitable armor. I know she's a berzerker type class, but you could make that argument for Charlotte as well.
3. That's just one of many nonsensical design trends of fates though. It just seems like you're selectively suspending your disbelief for things you like. It's not exactly a hyper-realistic setting, and while disliking unarmored inner thighs is fine, it's not as though it isn't internally consistent.
4. See #1 (I can see where you're coming from, but it seems inconsistent). I feel like the lack of shoes is a worse offense.
With regards to Xander's hair, it really doesn't bother me. I really like the male designs for Ryoma, Xander, and Laslow. For females, I like Rinkah, Velouria, and Peri (though I agree that her hair is a bit too much). Yuugiri/ Reina gets an honorable mention.