Not usually. Because most Saturns run a 4-bolt lug pattern, while all Crown Victorias run a 5x.5.5 5-bolt lug pattern. On top of that, Saturn cars run a 14" rim profile, whereas the Crown Vic has been setup to run a 15" rim.
Not without serious modification
Yes
Yes
Yes
Yes
Can 24's fit 99 crown Vic without lift kit
Mustang wheels will fit on a 2000 Crown Vic depending on the year of the Mustang.
Yes
can 5.0 engine fit in 1999 crown victoria
Yes
will chrysal rims fit ford crwn vic
Yes