At this time, calcium metabolism disruptions have been very rarely documented in caudates as opposed to other herps. Most of these documented disruptions were due to excess vitamin A (as retinol) in the diet disrupting the uptake and usage of D3.
Totally nocturnal and/or fossorial animals typically do not use UVB to convert provitamin D to D3 however, a large number of herps that are supposedly nocturnal but begin thier activity periods before sunset have been shown to efficiently convert provitamin D to D3 on exposure to UVB. I would suspect that most caudates do not need UVB for D3 production. IF there is concern then a good vitamin mineral supplement can be used.
With respect to UVA, it has been shown that it can be important for various behaviors such as prey recongnition and territorial defence (for example in Anoles and Desert Iguanas), I am currently unaware of any documentation that it is used in this manner by any caudate.
Ed