Sometimes you've just got to get on and do things. Overthinking some jobs can cost a fortune and still make the end result no better, but othertimes you will end up kicking yourself for not doing or checking something during the install.
If you were keeping the engine in the car its in now you wouldn't be contemplating changing the water pump head gasket etc etc.
But whilst the engine is out it will be worth splitting the gearbox off and checking the clutch and crank seal. Most of the stuff isn't hard with the engine in the car.
Good luck with the swap.
Paul