Hi Helen,
Here are all the Bacons I could find in the county, a few in the parishes you mentioned....
1664
BLITHE
Henry Bacone, jun., 1 hearth (not chargeable)
CROMWELL
Samuel Bacon, 1 hearth, 2s.
DUNHAM
Francis Bacon, 1 hearth (not chargeable)
GIRTON
Henry Bacon, 2 hearths, 4s.
LANEHAM
Abigall Bacon, 1 hearth, 2s.
John Bacon, 3 hearths, 6s.
LOUDHAM
Mathew Bacon, 1 hearth (not chargeable)
NEWARK - APLETONGATE
Martin Bacon, 1 hearth (not chargeable)
THORNEY
John Bacon, 1 hearth, 2s.
WELLAUGH
James Bacon, 1 hearth, 2s.
Richard Bacon, 1 hearth (not chargeable)
1674
CLIFTON
Richard Bacon, 2 hearths
DUNHAM
Francis Bacon, 2 hearths
Francis Bacon, 1 hearth (discharged by certificate)
FISKERTON
Ellen Bacon, 1 hearth (discharged by certificate)
HALLAM
John Bacon, 1 hearth
HARBY
John Bacon, 1 hearth
LOUDHAM
Mathew Bacon, 1 hearth
KINOULTON
John Bacon, 2 hearths
NORTH COLLINGHAM
Eliz. Bacon, 1 hearth
THORNEY
John Bacon, 1 hearth
WELLOUGH cum OMPTON
James Bacon, 2 hearths
Richard Bacon, 3 hearths
Also looking at the parishes you specifically mentioned, note that there is no surviving return for Fiskerton in 1664. For the other places you mentioned both 1664 and 1674 seem complete.
Hope you find this helpful,
Alexander