I’ll answer it in two parts:
Firstly, to avoid being in this situation you need to evaluate your workflow, it will work the way you have done it but it’s a backtracking process that can be completely eliminated, and it doesn’t work as well as sorting the workflow out. You shouldn’t dive into the details first.
Secondly the example you have given can be sorted with 2 zbrush techniques, zremesher (use it on a duplicate of the dynamesh) to create the lowest subdivision(your choice how low), divide it up to around the same count as the dynamesh was and use the subtool projection to project your details to the new model with low subdivision 
The best workflow for me inside zbrush is:
create rough shape and outline
Add low level detail
duplicate
zremesh
project low details(if needed)
Work up through the subdivision
This way you will always have a low subdivision level to easily use things like transpose master
Hope this helps
Everyone works slightly differently but the key thing to remember is to work the detail in up through the subdivision levels, and dynamesh works best for creating ideas in an instant but it’s not ideal for making characters to be animated or posed (moved in any way)