If you mount a brush hog on the front, you're going to find that, depending on rotation of the blade, you'll probably eventually puncture or damage the inside edge of one of your front tires with debris. At the least, you'll get a large buildup of debris on the inside rim of one of your front tires.
As noted before; my hog does not throw stuff toward the 3PT.
You don't want that brush hog hanging off the FEL arms. Think about how your 3pt hitch works. The brush hog rides on the tail wheel and your 3pt arms are not fixed in the down position. The brush hog is free to float the 3pt lift arms up if the skids hit anything. Your 3pt arms limit the down travel, but not the up travel. Your FEL is either locked or floats up AND down. There's nothing to limit the down travel. If you have it hanging from your FEL arms, it can't float. You need to have the FEL arms float and for that to happen, you'll have to put castering wheels on the brush hog, or put some kind of stops on your FEL rams to limit downward travel.
I have thought about putting 2 swivel wheels on the hog at the hitch end.
Also, how are you going to allow for going up a hill if you put a drive shaft on it? Your driveshaft will be fairly long and way out front. Do the geometry to see how steep of a hill you can have the brush hog go up before the driveshaft starts rubbing something under the tractor.
No matter what the PTO would be in two sections; a bearing point will be needed at the front of the tractor frame with that being the hinge point