MORE RHINO DRAWINGS! With your own original drawings! How did I miss this?
I'm not a big fan of realistic drawings, but I LOVE the Wick portrait. It's easily my favorite yet. It's perfect and I'm not exaggerating a bit. You mentioned wanting to do better highlights before, and I would say you did amazing here. The shading overall feels like a huge step up from your usual stuff, and your shading is already great in your usual stuff. I can see the smallest details like wrinkles on his forehead, and they're subtle and don't stand out at all, but you can still make them out perfectly and it's just amazing to me. It might just be that I'm too used to seeing animesque artstyle, where this type of details always stands out, but this really impressed me.
It just looks perfect to me, simply put. It's just beyond the level I can even criticize anything. I love it and it's my favorite.
Both versions of Ryo and Alice look nice. Since you colored it, I'm sure you must've noticed, but Ryo's left arm just looks alien. It's just really thin and the forearm is just too long, and I can't even tell how he's holding the plate. If it was just a problem with the reference you picked, I would just avoid using something like this as reference or try to fix it as I go along, rather than just ignoring it.
That's the only real part I would say needs any fixing. That out of the way, I have to say you did a lovely job with the coloring. This type of more subtle shading in color is pretty hard to get right, especially in analog drawing, and if it's off by a even a bit, it stands out too much, but you still did an absolutely great job at it. That's pretty impressive.
And finally, the original work! This is what I've been waiting to see you do for the longest time. You asked for heavy criticism, but there's not that much to criticize here.
Luffy looks pretty nice. His face isn't round enough to look like Luffy's. I'm not implying the face is poorly drawn. It's a normal face, it wouldn't be a problem in any other drawing, the shape just isn't very Luffy-like. The other facial features, though, are pretty good. It's just the shape.
And his right arm look a bit too long. At first, I just assumed it was because he's rubbery and stretching, but then I looked at the sleeve and even that is a bit too long, so I'm guessing it wasn't on purpose. These are the only two things that could use a bit of fixing. The shape of face and the size of arm.
For Zoro, the hands are the biggest problem. They're weird. I don't know how else to put it. I imagine you realize this too, since blackened them, but it still looks a bit weird. Now it looks like he doesn't have thumbs and he looks just unnatural holding the Katana. Actually, rather than holding the Katana, it seems more like the hilt of the Katana is just going through his arm. That's the main problem with Zoro.
Hands are hard to draw without reference to begin with, and you even tried to draw them holding something on what seems to be your first try, so I guess that much is to be expected. Even when you're drawing without reference, you don't have to draw everything without reference. If it wasn't working out, just use a reference for hands alone. Would work out better. Zoro overall looks great. The problem I mentioned is really minor. One of my favorite part is his facial expression. You nailed that. It looks exactly like something I would see in the manga. It looks great.
Hopefully, that didn't come across as being too nitpicky. Most of what I mentioned isn't a big enough problem to be noticeable at first glance. Mostly because you don't make many obvious mistakes. I'm looking forward to see more of your drawings without reference.