Option 1 is the introduction to Gypsy Jazz
Perfect if you're just starting out and need to get the basics of rhythm playing, take your first steps in soloing (improvisation), and the whole etiquette of how to participate in a jam session.
Option 2 workshops are suitable for Beginner to Intermediate players.
These workshops are great if you have been playing for a while, but want to build your confidence and take it to the next level. They may also work well for experienced players of other styles (outside Gypsy Jazz) who think they can pick up the basics fairly quickly.
Option 3 workshops are suitable for Intermediate to Advanced players.
You should have a strong rhythmic technique, and be reasonably confident with a range of approaches to soloing.
Option 4 workshops are suitable for Advanced players only.
You should be confident soloing over a wide range of gypsy jazz tunes, and be fairly comfortable with the theory underlying what you are doing.
Option 5 workshops are suitable for violin players of mixed ability.
Each class will cater for all ability levels.
Music theory knowledge is not essential (except for option 4 where it will definitely be beneficial), but will certainly be helpful in general.