Should we expect any major changes as we move from unweighted to weighted data analysis?
No more so than usual. Sample weights vary by age, sex, race/ethnicity as well as those variables included in the non-response weighting adjustment. So, for example, if your outcome variable differs by race/ethnicity then you could expect differences in the weighted and unweighted measures. For multiple imputation datasets, the sample weights do not change from imputation to imputation.
