As a paint, I can highly recommend the Alligator Kieselit Bio Mineral (dispersible silicate paint). For priming, I would not use Tiefengrund, but rather a pigmented primer (also available from Alli., as well as many other manufacturers). We tried both methods. On top of the primer, we had a textured roller coating or plaster base.
In my opinion, it is important to think through a proper system and, if necessary, invest a bit more money in it. In the end, it should be done properly...