The Packaging Tutorial assumes a normal package. If it's native (i.e. doesn't use patches), or if the upstream source isn't well tracked, or if the package isn't already in the Ubuntu repos, etc., things will break.
There's no need to use quilt if your change only affects the packaging and not the source code itself. For example, if you're going to change the debian/rules file, you can just make the change and update the changelog. In that specific example, though, since you are essentially changing the build instructions, you'll still want to do a test build.
Check out rDEFAULTSETTINGS and you'll find that in addition to the normal debian folder, there's also other files. Most notably there is a src folder which contains the code. This should be a clear sign that something is different, as Debian packages are nothing more than metadata that is applied to upstream source code. In this case, we do not use uscan to grab the source, nor quilt to manage patches, but just apply the changes to the code in the src folder and then proceed as normal.
A changelog entry is a requirement of every Debian package, but sometimes we're not working on packages. rSEED is a great example of this. No changelog to be found. No debian folder, even. This is because this isn't used to build a package that people install. It's used to build Lubuntu itself! You'll notice if you click that it's not on Phab, but on Launchpad. This will mean arc will be useless both for submitting commits, but also for merging them.
Or how to do a Merge Proposal on Launchpad.
or arc patching a fresh git clone to in turn arc diff