If the trailer doesn't have brakes, you need to add them. The first time someone pulls out in front of you, you'll plow them. My first 7'X12' didn't have them. I learned my lesson.
6' width isn't enough for the mower you anticipate buying, if you only have 3" of clearance. That doesn't sound right, as 6' equals 72" and you're putting 50" into it. That's a 22" difference; about the same as what I'm doing.
A V-nose would've allowed you to get all your perspective equipment comfortably loaded. I think I'd head down to your mower dealer with your 36" and see if the 50" truly will fit. Then, you can have time to plan over the winter if things don't fully workout the way you thought.
You have to be careful about weight, as others have said. I'm certain your tires are going to be the failure point. That trailer should have C-rated tires on it, which are 50psi max. With those two mowers on it, the tires will look like water balloons ready to burst. I upgraded mine to 15"X6" rims and Maxxis 225 10-ply tires (E-rated and 80psi). I kept the C-rated as spares. Some small trailers will not take that much width. Maxxis offer a D-rated tire in a 205 that is 65psi max and will gain you ~300lbs of extra capacity per tire. It's not much, but, may help.
Here's my setup, which may give you some ideas. I really do need to get a thread started.