Hi! New to Chef Talk, first post.
Its not difficult to add flavors to soft caramels, check out the book Chocolates and Confections, that will tell you everything you ever wanted to know about it.
For a direct answer to your question, though, for fruit caramels, if your making a 12x12 slab of caramel, add 12oz of hot fruit puree to the mixture when it gets to 234F or so. Dont worry about changing the cream ratio, when making the caramels, in addition to keeping the thermometer as a guide, you are always going to need to test the candy by hand in cold water. The boiling caramel mixture is too thick to be able to rely strictly on what the thermometer reads. But test it by hand and you'll get the texture you want.
As for chocolate, just add some chocolate at the begining of cooking, it will gradually melt and become homogenous.
Normally I'd say to just add an orange oil to the caramels, since it is a pure oil and not just an artificial flavor, but if you really dont want any oils, I would probably have to say that you can add a bunch of zest to the caramel and boil it in there, or infuse the cream with a large amount of zest and strain it before boiling. You cant just add orange juice to the caramel mixture, I think the acidity in the juice would invert too much of the sugar and your caramels would probably start to sweat shortly after they are set up.
A ginger caramel sounds delicious, thanks for the idea. I would pulvarize some ginger and let it steep in the cream for a day. Strain it the next day and start boiling.
As for others, try steeping coffee, I love doing that. Try different spices, anise or cardamom make great caramels, or just go with a simple cinnamon.
Hope that helps.