Iwannapool, welcome to the forum!! I have a couple things to say on what's been said on this thread (some of them may even be useful to you )

GPL for info on improving sand filter's performance, see thread http://www.poolforum.com/pf2/showthread.php?t=515 and look at Poconos' response. Also check out http://www.poolforum.com/pf2/showthread.php?t=6143 and read chem geek's and CarlD's responses (Richard gives 2 links on the subject) - <spoiler> it's adding some DE to the filter. (Carl, any chance of 'sticky-ing' the 'DE in sand filter' info? - it seems to come up fairly frequently - THX)

With reguard to the advantages of a multiport (not available on cart filters- but is on DE and sand filters) see threads http://www.poolforum.com/pf2/showthread.php?t=5319 (#2) and http://www.poolforum.com/pf2/showthread.php?t=5727(#6)

A preplumbed line may indeed have future use and will cost boo-coo bucks less to have it run when the pool is going in.

The Polaris is an automatic cleaner, often with a booster pump and designated line which runs off of the filter system and requires the pool pump (or a booster pump) to provide it with the suction or return water which drives it. A robotic cleaner works independently of the filter system (power source is in the unit and is motorized).

As a last, for now, note: the schedual of construction/ completion depends upon many factors including-
Builder competence and crew availability/ ability.
Weather!
Schedual of payments ('cuts' or 'draws') {check your contract as to what will be done before you have to break out the checkbook to pay him for work-to-date - USUALLY, THE MORE CUTS, THE QUICKER THE JOB WILL BE COMPLETED}
Unforseen difficulties (ie- hitting bedrock when digging an 8' deep pool)

As you said that you had 'finally' chosen a builder, I'll assume that you researched and compared prices/ products - CONGRATULATIONS! , if you did your 'pre-buy-work' then everything should go smoothly!

I'm sure you've gotten one of the top builders in your area and shouldn't experience problems with your pool being built. I hope you'll share some photos of the project when it starts next spring (and share any success stories of running your pool 'the PoolForum way')

Have a great winter and never hesitate to ask the great and knowledgable folks here any questions you may encounter!! - Waste