I have submitted questions to the FDA UDI Help desk on a similar issue related to convenience kits. One question they asked me was what was the product code of each of the components of the kits. You may want to determine the FDA product code for your items and ask the UDI to give a review to your proposed approach.
A conservative approach would be to have a separate UDI for each combination of kit component so that it would be easy to track individual kits in the event of a downstream recall. Since FDA hopes to use UDI for post-marketing activities, separate UDIs would allow the best statistical review of your separate product lines down to the "SKU" level.
Another consideration for risk management purposes - remember your design controls have to speak to this - is whether or not the kit components would every be separated for storage at the hospital or end user location. In that case, where separation is possible or probable, your company may wish to label individual components.
As an illustration, companies that are making combination product kits that contain PFS syringes are attempting to make decisions that answer all of these questions now. The answers they come up with for their product line may be different than what other manufacturers of combination products may determine, but each manufacturer must justify their approach in their Design History Files for future agency review.