Since you have plenty of time, take the time to thaw everything that needs thawing. Put them in the refrigerator late Saturday or early Sunday so when you go to prepare them they are completely thawed. Cooking from a frozen state is just asking for trouble, like being done on the outside and raw or even still frozen in the middle. Why take chances.
About the stew. What you suggested sounds fine, even good. Sometimes when a stew is allowed to sit in the refrigerator, the flavors can become so melded that everything tastes the same. By cooking your veggies before serving, they will retain more of their own flavor and will be an excellent accent for your stew.
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