Well first off, you might be better off using the newer syntax, which is way more intuitive.
With regards to your alternating row background question, here's how you do it:
$ifequal($mod(%tracknumber%,2),0
// if the tracknumber is even, the remainder when you divide tracknumber by 2 is 0
//Put your color for even number row here
,
//Put your color for odd number row here
)
Regarding your second question,
change your code to:
$if(%various%,%artist% - ,)
$replace(%title%,'(',808080|505050'(',
')',')')
$if(%skip%, 000091|910000*,)
$tab()
Again, the older column ui syntax is quite obtuse (specially when it comes to color). If you were using the newer syntax, instead of stuff like
000091|910000
for color, you'd have the more intuitive:
$set_style(text,$rgb())
$set_style(back,$rgb())
Updating the FCS to a newer syntax would definitely be a rewarding mini-challenge. You'd gain familiarity with the titleformatting commands and variables, thus enabling you to FULLY customize your foobar experience.