I know this is probably terrible, but I saw the shirt and the pants in my closet and I had to put them together at least once. The red pants were a hot topic of discussion for the "Terrible Fashion Blogs" thread a few months ago, actually.
I think the jacket seems formal in photos, but it's not. It's a cotton/hemp blend that comes off as quite casual in real life, especially since the jacket is quite wrinkled by itself. White OCBD = definitely, but I don't own one.
Ok, jumping here. I would get a shirt with a slightly floppier collar, I dunno if it is spread but if it is just burn it, spread collars are for bankers and british people and no one wants to be that. Otherwise it looks ok but not perfect. I don't like ribbon belts so I won't comment, nothing constructive to say. I don't see why this fit wouldn't be ok with sneakers but the black laces are annoying (you already knew). I don't think you're going for rumpled + dorty sneakers (like I often do) so I'd just get repettos for summer or some clean white sneakers (say the always popular common projects).