OSGI is specification, JBoss OSGI is one implementation of such specification. JBoss OSGI may be not being supported, but that has nothing to do with the general OSGI bundling support . Apache Karaf is another OSGI implementation, that is not associated with JBoss community, but it a very popular open source OSGI container. Teiid is developed in JBoss community, that does not mean we will completely ignore other communities nor ignore the trends how the community member like you are trying use Teiid in your environments. Thus, we started building Teiid components as OSGI bundles, that will work in any OSGI complaint container, and also happen to provide a entry point to use them in Apache Karaf OSGI container.
Note that above support in Apache Karaf is just providing a module loading, akin to providing a classpath all the jars, if you need to write a working Teiid system, you still need to do lot more work, just like the embedded Teiid usage.
If you are building custom components using Teiid, it is up to you if you want to build the OSGI bundles out of them or not, Teiid does not impose any restriction. If you are intending them to use in OSGI container then you have to, if you were going to use along with Teiid in JBoss AS/EAP, then there is no requirement for them to be OSGI bundles.