1. No, the stock ecu will protect the engine pretty well, it will just throw you through the windscreen if you boost it too hard.
2. Make a bung for the intake and pump 25psi into it. See if it holds air, you should be able to hear any leaks, or use soapy water to find them. Sounds like you may have mucked around with the boost bleed setup, did you replace the hoses to the boost solenoid? There is a restrictor in one...
3. Your dealer should be able to source a base map if he deals with HKS, otherwise you will need a later model Fcon Vpro which has the base map loaded. Have a search, the info is here somewhere. Speak to your tuner about it too.
That power target seems achievable on the SS1 highflow turbo, I guess you don't have access to e85 over there?