I've seen both B and C tractor conversions to foot brakes. Others might be able to tell you where to get them. When I was a young whippersnapper, TSC had the kits. I very much doubt they have them now.
As for safety, the B or C isn't so bad. The latching mechanism is nice on them - if you want to set the brakes on. I drove a C for many years in the steep hills of Wisconsin and had little trouble. For mowing, you probably won't need foot brakes.
On occasion, I had to drive the neighbor's WC, pulling loads of corn up a STEEP hill. About 2/3 the way up the hill, I had to stop, dismount, and open a gate. On a WC, this is no fun. Downright dangerous, if you ask me. The clutch needs about 4 inches of extra leg extension. The blakes were not easy to lock and unlock. The lock was a small cam on a swivel. Between depressing the clutch, taking it out of gear, pulling *both* brakes - and them locking them, I simply did not have enough limbs. This was a tractor that was screaming "foot brakes." Oh yes, you couldn't do the brakes one at a time - the steepness of the hill and weight of the load made the tractor "come around" on you if you had no braking on one wheel.
When mowing with the C, I had no problems - even on steeper hills.