Man that makes me cringe, whoever built that house and ran the plumbing that way is an idiot. Not much you can do now though unless you want to get the city involved and shut the street main and rerun a pipe. $$$$. I don't get why they did not make the pipe come out of the floor like it's suppose to, then run along the wall instead of sticking out from the side above frost level like that. That's not the cause of your problem though, but I just can't help but notice how crappy that install is from the get go (not your work, but the way it comes in).
As for the leaks, you need to ensure you sand the pipes real good, the inside of the fitting with a wire brush and the outside of the pipe with sand paper, and use flux equally throughout the sanded section. (I like to apply to both) Then solder until it starts to stick out a bit, but you don't need a ton of solder to be visible, it's what's inside that counts.
Here's some soldering to give you an idea:
I would not say that's expert though, was my first time, just practicing.
No leaks at around 100psi.