Agreed, the gelding is definitely good enough for hand walks but I'd be very hesitant to ride him for more than just a couple of minutes. For that reason (when I want to ride, I want to ride for a long time, not just a minute
), I'd avoid riding him. I wouldn't even touch the mare for more than bare necessities like having her feet done or de-worming her. Leave her with her face stuffed in a bale of hay.
I'd say the stallion could probably be okay for some very short walks but, because he's a stallion, I'd likely want to spend more time working with him near the barn to make darn sure that I had his respect and he was obedient on the lead. As others said, when he gets to feeling better, he might become a bit harder to handle as his stallion tendencies start to come out.