The starter is a nice plus for sure.
Spark plugs are a really nice plus for sure!
Can set up is tight but should not be a problem. The fan clutch (if your using that style) is available @ Hudson, they have what they titled the “Muscle Car Short fan clutch.”
Transmission bolts are @ the hardware store. (Use grade 5, grade 8 a plus!)
The real bear is hooking up the trans to the engine with the engine installed already. Getting your hands in the back to install the attaching bolts is already a bit of a PIA with small block.