Contrary to what his parries might suggest, Leroy isn't a defensive character. He can play safe yes, but he is designed as an offensive, close ranged stance character with parries and fast moves that let him take his turn back if the opponent tries to punish his gaps. You don't wait for them to mess up, you make them impatient with a flurry of blows and parry punish them when you have a read. You can choose when to be safe amd when to go in.
MID RANGE TOOLS
D1+2: your main heat engager but it's also safe with good reach.
B4: anti step mid that's safe and also has long reach. Can also be used at close range.
F4,4: another heat engager. Same purpose as D1+2 but has further reach.
APPROACH TOOLS:
FF3: a safe but duckable high that leads to a mini combo.
FFF3:Slower than FF3 but mid and plus on block.
FF2,2: punishable mid but gives a full combo.
UF4: An orbital heel. Jumps over lows, launches on hit, and safe on block. A bane for low get up kicks.
CLOSE RANGE TOOLS
1: The standing jab is the basis of every strategy in Tekken. Use it to check if strings are safe, to check for gaps, and to start your pressure. CH 1,1,1+2,1: great for taking your turn back. This string does nor combo together on a normal hit, so watch for the counter. If 11 combos together, thats your cue and you can mash 1+2 to complete the string.
DF1: your mid check to stop your opponent from blocking low. It's safe on block but stepping after can be a bit dangerous since you're -6 (-3 in Tekken 7), but you can parry after. Step once they start getting scared of the parry.
B1+2: a safe on block counter hit launcher that has short reach but is incredibly fast at 12 frames. Learn to love this move, it will reward you when getting out of tight mix up situations.
D3,2: your low string that goes into stance. HRM4 cannot be uninterrupted if this hits so use that to keep them from mashing and start your mid/low mix once they sit still.
B3: a new stance transition. Plus on block and tracks but is a slow high that can be ducked so use with some caution. Same mix as D3,2
DB1+2: Your main parry that is also a heat engager. Use this if you think your opponent will try to mash after DF1.