Minimal Postfix master.cf
I wouln't recommend you to remove service from the default master.cf. You have been bitten by it when you tried minimalist config.
One reason why postfix has many service is security. One of advantage is postfix run by separate daemon/service to do specific task. So, postfix master can adjust permission and privilege per postfix service. For example qmgr(8) daemon does not talk to the outside world, and it can be run at fixed low privilege in a chrooted environment.
Anyway I don't have time to do endless trial and error in order to know what's postfix service that can be disabled. So I give you some info about some service and grouping it by several groups.
# INPUT SERVICE
smtp inet n - n - - smtpd
#submission inet n - n - - smtpd
pickup unix n - n 60 1 pickup
# PROCESSING SERVICE
cleanup unix n - n - 0 cleanup
qmgr unix n - n 300 1 qmgr
rewrite unix - - n - - trivial-rewrite
# OUTPUT SERVICE
error unix - - n - - error
retry unix - - n - - error
discard unix - - n - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - n - - lmtp
smtp unix - - n - - smtp
relay unix - - n - - smtp
# HELPER
# Generate bounce
bounce unix - - n - 0 bounce
defer unix - - n - 0 bounce
trace unix - - n - 0 bounce
# For postfix recipient/sender verification See www.postfix.org/ADDRESS_VERIFICATION_README.html
verify unix - - n - 1 verify
# Outgoing Connection manager
scache unix - - n - 1 scache
# TLS Cache Manager
tlsmgr unix - - n 1000? 1 tlsmgr
# maintains statistics about client connection counts or client request rates
anvil unix - - n - 1 anvil
# Needed by mailq command
showq unix n - n - - showq
# Needed by postqueue -f
flush unix n - n 1000? 0 flush
# Proxymap
proxymap unix - - n - - proxymap
proxywrite unix - - n - 1 proxymap