I can observe similar difficulties here, although I think that the “lack of gapless” may in fact be gmrender-resurrect cutting off the first half a second or so of the audio of each track. I believe that someone has filed a bug report on the gmrender-resurrect git page about this, but the developer does seem to be rather busy, unfortunately.
As to it working fine when following the tutorial, standard Raspbian does not use gstreamer 1.2 but gstreamer 0.1. This may be the relevant difference. The developer of gmrender-resurrect has reported that there are bugs that prevent gmrender-resurrect from working correctly with gstreamer < 1.2 which is why I spent 2 days backporting the packages. If this is the problem, then using method 2 on my web page may help.
If that’s not the issue, then all I can tell you is that the page you quote was one that I used in creating the original package. I was in essence following the same instructions you did, so it could be anything from a difference in asound versions to a different version of the kernel modules to some other difference I’ve not thought of which has caused the problem since your initial compile. If you have a working and an non-working version, then comparing the differences in infrastructure between the working and non-working versions may help us to narrow down the culprit though.
I’ve tried with both standard audio out and a HifiBerry Digi board. I don’t think that the issue is device dependent. Unfortunately I can’t even track down the cause with the information we have, yet alone fix it. Sorry if my frustration came across as hostility to your difficulties. I agree that gapless playback would be very desirable, although in truth I’ve never come across any “gapless” solution for MP3 which didn’t involve at least a little “bump” between tracks. This was (is? - I haven’t had a working device capable of running Rockbox for some time, sadly) certainly true of gapless support in Rockbox, for example.