Which measurements are most important to consider for tall men?
Among quality aka dealer-level bikes, each model comes in a range of sizes. Wheel size in and of itself is immaterial to fit. Published weight limits are not typically contingent on frame size, i.e. it's the same number for the whole size run.

There are questions on here about how to interpret weight limits, but most dealer-level bikes are somewhere around 300lbs, especially for more entry-level bikes.

All but the biggest bike companies wrestle with economies of scale for bikes on the far ends of the size bell curve, so that's usually the main place someone your height will need to look. In other words, you're likely looking at barely squeaking in, if that, on an XXL hybrid or MTB, and many companies only go up to XL. In the US, brands I know that do XXL on a lot of bikes are Trek, Specialized, and Cannondale.