the snap ring is to the rear of the bearing. Clean out all the grease and if there you need a very long set of snapring pliers to remove the ring. There is no need to replace the ring if using a new style bearing
pic 2 looks like the oil pressure alarm switch. It closes when there is no oil pressure and trips a buzzer or horn.
Pic 6 is the oil pressure sender for the oil pressure gauge.
If the nails were corroded so are the pins and there not coming out, you can try forcing them inward to shear the nails ,but...........................................
A replacement housing is highly recommended
you dont have a choke plate if its a TKS carb and you have no active control of the choke if you do have a choke plate
I have to keep the choke in or else the engine will stall.
