I'm fairly sure that the 70-81 windshield is the same dimensions.
Yes it should.
No
A 1973 Firebird bumper will not fit directly onto a 1976 Firebird due to design changes and differences in mounting points between the two model years. While both are part of the second-generation Firebird lineup, the bumper shapes, sizes, and attachment methods vary. If you want to use a 1973 bumper on a 1976 model, modifications may be necessary. Always check compatibility and consult with a specialist for specific fitting advice.
No, they are 2 different bodystyles
No It won't fit unless you use the 76 + windshield with it.
Simple answer...yes. Not much changed between the years until 81.
no one cares
That depends on the make, but not likely with that many years in between.
NO!
Yes.
Yes, the windshields should be the same.
Yes it will fit, They are exactly the same body style