Centric 130.40078 is the Master Cylinder for the G1. I bought it Aug 2018 and had it installed when I changed my brakes a couple of months after that. Centric is a very good company with great reputation and reliable parts and respectable warranties. It was a straight bench bleed, install and full system bleed. Not sure who said only the dealership can do the brake bleeds on these.
Also, the tie downs are a shitty thing from the previous owner. Sorry bud. You can drill them out and tap them to put new bolts in.
I echo the title part; I would have not purchased it without a title. Since you say you will have it and you are confident, then I guess its all good.
Non electronic mechanical parts can be swapped out to non-Honda units and still perform the same, if not better than OEM. However, if they are electronics, it is best to stick with OEM. Like, lets say, O2 sensors, Coil packs, spark plugs, MAF sensors, etc etc. You can change the radiator and condenser fans to non-OEM and be fine with it. Use ROC to search for things and ask questions, prior to indulging yourself in the project.
Engine operation, along with the driveline operation, are PCM controlled. For a safe performing vehicle, I would not by pass anything, till I am sure what I am doing is not going to affect the safety and performance of the vehicle.