The engine support brace wont help you. When you install new engine mounts you need to actually raise the engine a bit to get them out. The engine support brace only does what it does , support, it doent raise.
Put a block of wood under the oilpan and raise the engine with a jack until you get them out. Nothing is gonna happen , dont worry , you're not gonna mess up any wires and your oil pan wont crack or break . Done it many times