The 3 TMS1000 handhelds you decapped are emulated and playable in MAME now. I'm not sure about the Brain Buggy MCU clock frequency, could you double check the RC values? If 2 "TDU" steps is 1 second (according to the manual), MCU speed should be around 100KHz or even less.

Regarding Sub Chase HD38132 vs HD38800 from Kingman, do they look much alike to assume it's the same (HMCS40) family?