@sonofel! I hope you’re not getting overwhelmed with responses trying to help. But I suspect many are feeling your pain, because (at least) I have been there as well.
Using Eclipse with Maven projects is indeed confusing for beginners. You can spend a lot of time solving problems that don’t really exist. If you’re ever suspicious of compile errors, first thing is to do Alt+F5 (Right-click the project, and select Maven > Update Project). This updates Eclipse’s IDE with the real compile situation as define in your maven pom.xml file. pom.xml is what counts in the end.
In case you are working to develop a client, I can also give you a pointer to a recent client code that works with the latest Lyo 4.0.0-SNAPSHOT. namely, client-oauth-discovery-dui.
It is recently developed, so it should be more stable. I have not used it against Jazz-based systems, but other similar platforms.
Finally, if you’re considering using Lyo Designer, worth mentioning that the latest version automatically generates the maven-related files for you. This basically means you don’t need to do any of the steps under OSLC Server/Client Setup
I have not had the time to document these steps, but if of interest I can give you quick pointers.