It seems that the correction is trivial; I had not grokked-to-fullness the fact that Admin privileges may be added or stripped from whatever 'User' and even multiple 'Admins' (!) can be created/destroyed by the mere click-a-box. Then, magically a huge litany of Permissions get redrawn. [One Hopes]
Am enroute shortly to employ this perspicuous insight to remedy her situation and 'reset'/erase the db in Time Machine to begin anew, unflummoxed by such basic changes in nomenclature of its Users.

ie WIll create a new Admin; add Safari and little else. Then rip off the epaulets for current admin-User, within whose sinecure resides the mentioned stuff loaded off Bestware, etc. That, renamed, shall be her Surfer. No need for wiping and serial-think, from scratch. Duh.
She will never ever login as Admin anyway; all will be via sudo, whereby she will drag out her Admin-Name and pw crib-card, for each Update and the like.

(But I shall have twitted someone's nose in the Edible-pome hierarchy -- about ever sending home again a evident Newbie, as Admin with pw [blank] and firewall turned OFF: in Any Store!
I SHALL Do This, or my name is not Walter Mitty..

Yeah, I don't intend to purchase Intego's NetBarrierX5 either, though it's er, granularity greatly exceeds the KISS of Apple's perfectly-adequate built-in.. (Which also saves forever the useless clutter of any HS connection ... gotta discover what the default is for clearing out that clutter; I only gots 320 GB.
Just happened to notice, when I ran the free CLAM AV (in SnowLeopardCacheCleaner) -- the list of known rootkits.
Yet, as we all know: as Apple's actual's %action rises, there will be Attacks, hmm, maybe even foreign?/domestic-Corporate-spawned, depending on the paranoia weather each day. I no worry, for the nonce.

And, for there being no plug n'play router Model I found to have the slightest chance of my configuring exactly right: I no router firewall, at all.
(All the specimen ones I researched, where any reviewer mentioned Apple, gave one or more horror stories of nonexistent support and indifference to OS X installation. Required (for me) heroic intervention and maybe even firmware hunts at Mfg website etc. Stupid, that. Apple's answer is their wi-fi-combined thingie; too $dear, and I want WIRED-only. Until a decent iSomething notebook drops from the sky into my lap some day.

Oh and -- the Santa Rosa CA 'Store' is a mere cave-type box-in-the-Mall: it is Certified to be Apple's smallest one!. She had already ordered One2One BUT: the cacophony is so huge in that echo-chamber ... it is unlikely to be bearable. She'll find out and decide whether to get back her fee.

Gracias,
A.