YES 1998 - 2005 are built on the b5 Platform. Many parts are interchangable. In this case I sencond the yes.
yes
With an adapter Yes.
If it is from a Passat, with the same year, it should.
Yes and no it takes some customization to make it fit.
It will fit if it is a mid production 99. Early production Passats will have a different part number. Check with your local VW dealer's parts department and have them do a cross reference of your cars production date and the part number for a 2000 model.
No. Its 1.5 DIN
Will a 1998 3.8 mustang engine fit in a 2000 Mustang 3.8 engine?
No, none of those will fit without extensive fabrication.
Yes, wheels from a 1998 Mustang will work on a 2000 Mustang.
No
Depends on what the "2000" engine is...
will 2002 monte carlo rims fit 2000 s10