Lee
Couriouly, we are just working on submitting a paper about estimation methods for multidimensional IRT. My Bayesian code worked well even with small sample sizes, the average bias is around 0, and the model priors constrainted the parameter space to prevent improper solutions. The major issue is that the bias variability increases at lower sample sizes, mainly due to sampling variability as an small sample might vary further from the overall population
I cover several of these model and methods in my BSEM summer course in the Stats Camp, for BSEM I use blavaan, and for IRT I use the syntax models from the github
Hope this helps