There is not loads of clearance if you want to keep those mudguards.It definitely will but you could probably eliminate that with larger tires
The braking is only one part of the issue. Hit a pothole at 20mph in one of those, and see what happens.I could change the brakes to hydraulic so that removes that problem.
There are much better bikes to do a conversion on, honestly. I would much rather have an MTB with a suspension fork for this.