The real question is, "How many days is it going to take to follow all those steps?" You have turned a simple 2 minute process into a research paper. WHY would you install a temporary valve? TEMPORARY means it will be removed, and then you have to make two new connection to fill the void where it was. That means you have to perform most of the process again to test those connections. Here is what you do;
1. Look at all the connections to be sure you actually soldered them all.
2. turn on the meter, with someone in the room in case of a major mistake. Ideally with their cell phone connected to yours.
3. If there is a "major mistake" they will shout to you or use their cell phone to tell you to shut it off.
3. Check the piping.
4. Wait 30 minutes and then close the walls.