#1
i'm not too sure what goes into a guitar setup, but will getting one on an acoustic fix the intonation? i can get an open A to sound in tune but the A barre chord never is.
#2
A good guitar setup will involve:

1. Checking action at the 12th fret and adjusting the saddle if necessary.
2. Checking 1st fret action and adjusting nut slots if necessary.
3. Checking neck relief and adjusting truss rod if necessary.

The results of these adjustments are interdependent and if done properly should sort any intonation issues with the guitar (assuming the guitar is reasonably well built in the first place - but even poor guitars will show improvement in playability and intonation).

A good guitar tech will also check the general health of the guitar and advise if there are any issues with tuners, humidification, etc..