Seminole questions...
The hydraulics for the brakes are simple, just like the brake system for most single engine cessnas...Msster cylinder hooked to both sets of pedals and linked to the brake pads
The hydraulics for the gear are independant of the braking system...The gear is electrically powered, and hooked to a reversible hydraulic pump...If you have the jeppeson multi engine handbook ( the old one ) it looks exactly like the one described in that book. Basically, pressure holds it up and locks hold it down. 3 green and your okay, any less or a red unsafe light and you got problems...Try switching the lights or recycle it, and if nothing happens slow to 90, lower the gear handle, and pull the emergency extension knob. All it does is relieve all hyrdraulic pressure, which is what holds the gear up, and it'll freefall down. If you don't get three green right away, fishtail the plane with rudder...This way the relative wind will hit the gear doors and help to force the mains into the downlock hooks.
As for either engine catching fire, use the standard L shape flow check for dealing with it
-Fuel Valve off
-Mixture Idle cut-off
-Prop to feather
-Throttle to idle
Open the cowl flaps on the engine you just shutdown and look for a place to land. ( Usually right below you and within one minute of flying time )
Thats pretty much what the POH says for both situations...
Hope that helps