I have four, four-item subscales that I'd like to use in a mixture model. Currently the subscales are continuous and thus I want to conduct a latent profile analysis (LPA). However, given that this LPA would only have the four indicators (one of each subscale), I can only extract up to 3 latent classes before my degrees of freedom become negative.
Could I embed a CFA into the mixture model, so that each subscale's items indicate a latent factor for that subscale, and those latent factors are used as indicators in the LPA?
Is this A. feasible and B. something that would overcome my negative df issue, so that I can extract more possible classes?