Rabbit is having small, black poos

I first noticed Bugs's poos being off a few weeks ago but just today they've been small. There is lots of dark poos. I am positive they're his poos. On top of his poos being dark, one of his eyes is leaking. It isn't leaking bad but the fur next to his eye leading down his face is clumped together. I can definitely tell a difference between the fur around his eyes. He has been sneezing more than before lately, but that may be because I've been paying extra attention to it recently. He is acting completely normal.

Some background information:
He's a little over one year old
He's fed timothy hay (topped 2-3 times daily), 1/8 cup Oxbow Adult pellets, 2 cups of veggies daily (Including kale, romaine, green leaf, red leaf, spinach, bell pepper, cilantro, parsley) veggies vary week to week.
He shares the same living space with my female (who seems to be healthy now)
Our cat recently got an eye issue that caused his eye to leak (can't remember the name of it)
At his vet appointment last month, my vet had mentioned that his nose seemed wet and asked if there had been anything coming out of it. I haven't noticed anything coming out of it but it does seem wet.

Any help will be greatly appreciated! Below are pictures of the litterbox they share. The normal poos are my female's. The dark color is hard to see in the picture for some reason and same with his eye picture. One picture is of his good eye, sorry it's dark.

After doing a little more research, I found out the darker poos are either caused by bleeding in the digestive tract or a low fiber diet. Alfalfa hay has the most fiber out of all hay types and I think I may get a bag of that and see if that makes a difference. In his salads recently I've been feeding kale and while I've never noticed anything serious, he doesn't seem to do well when fed kale. It usually makes his poos smell bad. When I got veggies last week, they were out of red leaf and I didn't want his salads to just be romaine and green leaf so got kale. He usually isn't fed it so it would explain his poo issue. I need to get veggies today so I won't get kale and see if it changes anything.

You mean the droppings with a little darker color. I would say it’s the hay or a imbalance in his stomach.

I often get it on my doe, I just let her eat a day of hay and everything goes back. I also bought a pellets that are supposed to help rabbits that get an imbalance of bacterium in the stomach.

It worked great for my doe and she got a more stable droppings than before [emoji5]

Also some veggies will make the droppings changes, even change of hay can make the droppings a bit darker