Thanks Dark Shade, so if I'm getting what you're saying, the blue abilities (ie. cannon arm) augment the green abilities (ie. arm strength), so that a player with A arm strength would still not throw as hard as a player with A arm strength and cannon arm - is that right?
If so, then here's a follow-up - what would happen if you had a player with G or F power, but also had the power hitter ability? Or low contact but contact hitter, that sort of thing. It doesn't appear that there's a requisite level of contact (green) that a player is required to have before taking the contact hitter ability, so which one is more important when it comes time to playing a game?

Thanks again DarkShade. Since you obviously know what you're talking about, I'm going to pick your brain a bit more then.
So if I'm working on a success player that I want to then use in Season mode. I want him to be able to hit 20-25 taters a year and bat around .320 let's say. If he's got a high rank in power, let's say B, and say level 4 trajectory, in big swing mode he'll definitely jack a few, but he'd probably also hit some doubles to the wall which, if he had the power hitter ability, would have carried out of the park. Am I reading this right? Similarly, a catcher with B arm strength would throw out his share of runners but one with B arm strength and a cannon arm would throw out more. I think this is what I'm hearing, correct me if I'm wrong.
By the way, you're right, I was referring to attributes rather than green abilities - my rookie mistake. My original question, which you've done a good job of answering so far, really boils down to attributes vs. abilities and which are more important for playing come season mode? Thanks.

I'm still a bit unclear as to when you would want to choose something like gold glover over increasing your player's attributes in fielding and error resistance, but I'm starting to catch on I think.