The Lesabre used different seats, not sure if they have the same mounting points or connectors. The Bonnevilles were the same as the Aurora 2003-2005, but 2000-2002 were different (once again, not sure about mounting points or connectors).
Deville seats appear to be completely different, and most likely have different connections due to separate back and bottom cushion heating element controls (and ventilation controls on 03-05). The Seville seats likely would fit (just a guess based upon the similarities in the platform), but may have different connectors.
2001 Intrigue GLS - 208k miles, lunchtime runs only 2002 Aurora 3.5 - 110k miles, daily driver 2002 Aurora 4.0 - 141k miles, not long for this world
Other cars currently in my fleet: 2003 Impala LS (3800), 2005 Yukon XL (5.3), 2017 Chevy SS (6.2 w/6spd), and 2013 Audi A8 4.0
Former cars (i.e. leases that went back): 2007 Hummer H3 (5spd), 2012 Chevy Volt, 2014 Camaro SS (6spd), and 2015 Terrain SLT V6
Totaled: 2008 STS (Northstar) (slid on ice into a tree at 55mph)