#1
http://www.rondomusic.net/sxguitarneck.html

would this be a good improvement over a squier neck?

the only thing my friend is keeping of the squier is the body (its alder, which looks great and sounds not that bad)

so would it be a good replacement? obviously its a low price strat style neck so if its decent he'll probly get it.
#2
It will probably be the same as a Squier neck. Your friend should by a decent Fender licensed neck, cause that's important.

American Stratocaster + Blues Junior

#3
why dont you just sand off the old finish on the squire neck and refinish it with urethane? thats what i did and it plays beautifully.
The Gear:

Custom Strat
Mesa Boogie Stiletto Ace
Fulltone OCD
Electro Harmonix Small Clone Chorus
Dunlop Crybaby Classic
MXR EVH-117 Flanger
Fulltone Soul Bender
#5
unless he's just re-building his squire for fun and for the hell of it (in which case never mind what i say), i'd say just get a new guitar, between buying parts and paying installation fees it'd probably cost the same and have a better result.
#6
^No, that would be copyright infringement.

And anyway, I think the necks are the best parts of Squiers... why change?