What Kinds of Data are Suitable for RMLCA?
The indicators of latent class need to be categorical (variables on interval or ratio scales could be converted to categorical variables). If you have interval- or ratio-scale indicators, you may want to look into profile analysis as an alternative to LCA. If you are looking at modeling several repeated measures of the indicators, it is best to keep the number of indicators and levels per indicator at each time point low.
Covariates and outcome variables can be continuous or categorical. Missingness in covariates is a problem, however.