i pulled the following from mccc documentation. these won't solve all your problems, but they'll help with some.
MCCC > Flag Active Sims... > MC Pregnancy > Flags Affecting Marriage/Relationships > Flag Never Marry (no random marriages, applies to all active sims in household)
MCCC > Flag Active Sims... > MC Pregnancy > Flags Affecting Marriage/Relationships > Flag No Romance Move-Ins (no random romance move-ins, applies to all active sims in household)
MCCC > Flag Active Sims... > MC Pregnancy > Flags Affecting Sim Pregnancy > Flag for No Affairs (no random affairs, applies to all active sims in household)
in order to prevent random death, i would just flag all sims i don't want to die as immortal, then unflag them when i'm ready to let them die. maybe someone else has a better solution, though.
edit: oh, i was clicking around & found some other settings. these you have to access by clicking on the computer
mccc > mc pregnancy > marriage sim selection > bypass played households (when checking for random marriages, bypass any played households rather than just the current active household)
mccc > mc pregnancy > marriage sim selection > bypass active sim romances (during random marriages bypass sims that are in a significant-other relationship with an active sim)
mccc > mc pregnancy > pregnant sim selection > bypass played households (when checking for random pregnancies, bypass any played households rather than just the active household)
mccc > mc career > bypass played households (when assigning careers to Sims, if this is true then any household marked 'played' will be bypassed by the sims 4 career-assignment process)
