Looking at some numbers there are 14 brackets that have 16 or less wrestlers. Out of those 14, 7 will not have to wrestle a match to make it to state.

8U
125 9 wrestlers

10U
52 14 wrestlers 12 will make it to state
150 16 wrestlers 14 will make it to state
170 8 wrestlers

12U
64 14 wrestlers 11 will make it to state
215 9 wrestlers
240 4 wrestlers

14U
75 4 wrestlers
80 8 wrestlers
85 15 wrestlers 12 will make it to state
265 16 wrestlers 14 will make it to state

HS
100 9 wrestlers
106 16 wrestlers 12 will make it to state
250 13 wrestlers 9 will make it to state

So there will be a total of 20 wrestlers staying at home that could be used to help fill brackets.
If you include the rest of the brackets it breaks down like this.

8U
110-4

10U
52-2
55-4
130-4
150-2

12U
64-3
190-2

14U
85-3
90-1
160-1
235-1
265-2

HS
106-4
113-4
132-1
250-1

Grand total of 39 who could help fill brackets.