to name a few ... My question is: Which of the words is most likely to approach the realm of being an unnecessary peripheral in your judgment? Subsidiary seems to be the least essential to me, but maybe not

Assuming your own list is not exhaustive, Wordwind [from your preface "to name a few"], I would like to add:

accretion
accoutrement
flourish
embellishment
accent
frill
minutia
accomplice

and, from this appendage, I would choose "frill" as "the most unnecesary peripheral".