I am not sure about freelance gg's. Freelance lbs, yes you can get one for 1000 Baht short time - but that is not generally for the really attractive ones, or if the rent is due at the end of the month and they need the money. 1500 Baht is the average for a freelancer lb.
Very few lbs do LT anymore as they make much more short time. ST generally means 1-2 hours (depending on when you orgasm and also the lb in question). LT used to mean until the morning, but as mentioned very few lbs (and possibly gg's) will do LT any more.
Soft drinks in Obsession was about 120 Baht, in Cockatoo and Shadow (the 2 Soi Cowboy lb bars) it was 160 Baht. For the lady drinks, it depends on whether she orders an alcohol drink - if so expect 200+Baht, if a regular non-alcohol lady drink probably around 180 Baht.
The Obsession lbs are not as pushy for drinks as the Soi Cowboy lbs are, Likely because Obsession has more customers and the lbs there make more.
I would say the Obsession lbs are also on average more attractive (if you like the more curvy, busty ones), There are more "femboy" types at the Soi Cowboy bars.
I haven't made it to the lounge bars, but from reports and Facebook photos, it seems Check In Bar has the most attractive lbs and more numbers on staff. The Facebook page for Cindy's Secrets looks good too, although she doesn't have as many lbs on staff (likely being a smaller bar in size than Check In or Why Not). Why Not has the advantage of a Western host at times, as he is married to the owner.
Freelancers start showing up around 9:00 pm, but the biggest numbers will be out between 11:00 pm - 1:00 am, The bar lbs sometimes will go freelancing after the bar closes if they didn't get a customer or no lady drinks, so there might be a surge in the freelancing numbers after 2 am. (Soi Cowboy closes 1:00 am).
If you are just drinking with a bar lb and don't barfine here, a reasonable tip is 200 Baht (but if you were french kissing her and feeling her up in the bar - a bigger tip is in order if you don't bar fine her).