1. I always make starters, or pitch enough slurry based on
http://yeastcalculator.com/ or
mrmalty.com but this is a relatively small beer so its not entirely necessarily if youre using S-04 as the dry yeast should have plenty of cells for a healthy fermentation.
2. I do adjust for mash PH, i shoot for
Burton on Trent profile and a mash PH 5.3
3. I do a 7-10 primary, then rack to a keg where I dry hop for 4-5 days in a nylon bag suspended in the keg. Once the 4-5 days are up I remove the dry hop bag and throw it in the fridge and connect the co2. If youre bottling I would just suspend the hop bag right in primary for 4-5 then rack to your bottling bucket to bottle. That would put you at ~15 days i primary including the dry hop, which should be perfectly fine. You could rack to secondary and dry hop there and then to your bottling bucket but I am a proponent of as little racking as possible.