One of the things that helped me greatly with coordination....3 way coordination to me is fairly easy. When the 4th limb becomes involved, the difficulty increases exponentially...for me anyway. So what I do to break through the coordination barrier is to first sing (without playing it) the part I'm struggling with. If I can't sing it, I can't play it, truth.
In your case, it's your left foot. So, while letting your left foot go limp....don't play it...sing only the part that you would like to play with your left foot. If you are like me, singing it still throws me off. It's easier to get past my coordination issues by just singing or vocalizing the part that's throwing me off. Even grunts work. It's still difficult, but it is easier to sing the part than play the part. Once you are able to vocalize the problem part correctly, even with grunts, you really should be able to actually play it.
If you can do 2 and 4 on the hats, you really should be able to play it on 1 & 3 as well. Maybe try that to start to play different figures on the HH.
But yea, sing the problem part at first, don't try to play it until you can first sing it. It's one of those hard learned lessons that I had to figure out. It really helped me to break through coordination issues. I feel it's the quickest way forward when I can't do something. Your brain has to coordinate with itself before your limbs can get on board.