There are no covering defenders. There's the one committing the foul and the keeper. The other defenders are behind and would not be in a position to intercept.
Regarding the doubt question. It's not black and white, off/on. It's shades of grey. A scale. How likely is the attacker to control the ball? There's 'very easy', 'no chance' and everything in between.
It's like direction to the goal. When an attacker taps the ball to go around a keeper and is fouled - there's a point where you can't argue they're going to goal, and a point where you can't argue they're NOT going to goal. Then there's everything in between. Where in that scale I pin the tail on the donkey and say 'at this point it's obvious' might be different to where you do it.
Obvious is a subjective decision. Remember we're only dealing with an obvious CHANCE.
And because it's subjective, sometimes we push that decision. If it's a really low grade, social match, simple innocently mistimed challenge, 6-0 and it's one of those 'kind of angling away a little', then we're probably going to push that 'direction' argument as far as we can to keep them on the park - but there's a point where we can't. Similarly, when it's a blatant, intentional foul to deny a goal, I think we're more likely to want to send them off if we can justify it. And that, I believe, is within the spirit of the game.
Here, we have blatant cheating to stop a goal. So, I'm not wanting to search too hard to keep him on the park. If I can't justify DOGSO then I Can't, but where it's at that grey, subjective point - well, I'm pushing it towards the red here.
So, as I said there's an obvious CHANCE. I'd say that, taking the fouling player out of the equation, there's a very good chance the attacker will reach the ball before the keeper. The ball is closer to the attacker and dropping. It'll be close between them, but I think the likelihood is of the attacker getting there first. If he does manage to take a controlling touch, then he's in an OGSO with only the keeper to beat. Is the keeper too close to the ball/attacker for the attacker to be able to take a controlling touch? Maybe, but, I think the attacker at least has a clear and obvious opportunity here.
So it's a red for me. But if I was assessing, I may accept a yellow if the reasoning was sound.
IF you're going to say that it looks little better than a 50-50 between the keeper and the attacker, then I can accept that. It's not a 50-50 - IMO the attacker will reach it first - but there will be disagreement over whether the attacker can reach it early enough.
I think the blatantness of the action and the spirit of the law expects us to try to give the red here if we can justify it.