Mark,
4B1E1B decodes to HB-LKL which is not assigned. Previous holder of the registration is now C-GEON, Piper PA-27-250 Aztec F, c/n 27-7754153
4CA4B1 unknown
A51D6A decodes to N429DS not assigned by FAA. Only previous holder of the registration I can find is now D-ENWR DA40
ADFEF4 does not decode
C005DD C-FCFS, Cirrus SR20, c/n 585, David Codack
Regards
Alan