Mike is my brother's name.
The fuel leaks are causing your starting problem. When mine was leaking, it had trouble starting whenever the tank was less than half full. My solution was to either keep the fuel tank full or park nose-down in the driveway.
You can also hold the key in the start position (rather than letting go right away) to crank it a little longer if you expect a difficult start. It also seems to help to hold the accelerator to the floor to pump as much fuel as possible through there. Of course, once it starts to fire, you let up.
As for changing the shut-off valve without removing the manifold, I could probably do it now that I've done it. But then again I'm 6ft tall and weigh 145, so my arms are long and thin. For someone of more "average" size, and for doing it the first time, I recommend removing the manifold. It's something you should learn to do anyway, and it's not really all that hard. My biggest problem was that either the manifold or the EGR valve was not machined properly, so the bolt holes didn't line up. Apparently, the dealer tech didn't really care last time he worked on it, and he stripped the allen head bolt that goes in there. So I had to take the next section of pipe out with the manifold. Not pretty, but I got the job done. Hopefully yours won't be as difficult.
I haven't done any resistance testing on these plugs, but it would seem to be the same as the others posted here. My experience is that these glow plugs seem to last about 40,000 miles. And of course you'll want to replace them all at the same time since the manifold has to come off.
It's really not all that scary, but the dealer seems to think so. As soon as they say "intake manifold" it's ka-ching - another $500. Did you find Lightman's post about the glow plugs?