Hello everyone,

I will really appreciate if you kindly suggest me how to develop correct Mixed Effect Models for the following research objectives:
1. to examine the extend to which the effect of immigration status (the variable contains three categories: Native-born, Recent Immigrants, and Long Residing Immigrants) on the mental health (the variable, MH, the Positive Mental Health scale) vary in term of region of residence (the variable contains 5 categories), regional economic condition (regional GDP, it is a discrete variable) and regional composition of minority people (the variable contains total number of visible minorities by region, the variable, VisMin, is also a discrete variable).
I am planning to develop the model like:

mixed MH c.GDP##ib1.immigrant c.VisMin##ib1.immigrant [pw=WTS_M] | | Province: ib4.Province#ib2.immigrant, covariance (unstructured) mle

2. to examine the extend to which the effect of post-migration stress (the variable is a scale) on the mental health (the variable, MH, the Positive Mental Health scale) vary in term of region of residence (the variable contains 5 categories), regional economic condition (regional GDP, it is a discrete variable) and regional composition of minority people (the variable contains total number of visible minorities by region, the variable, VisMin, is also a discrete variable).
I am planning to develop the model like:

mixed MH c.GDP##c.post-stress c.VisMin##c.post-stress [pw=WTS_M] | | Province: ib4.Province#c.post-stress, covariance (unstructured) mle

Can you please with your comment on the model plan for my model plan?

Attention Clyde Schechter Carlo Lazzaro please