From what i read you can stake any amount you want and get a certain % on it. I have seen mixed articles on Amount Staked VS Return VS Staked Timeframe. You just risk the "loss of sale option" if, for instance, a fork is hackable or a MTGOX situation.
As for price Im expecting a slight drop right after the update then a slow climb over the month. You will be losing miners but people will flock to a "dividend" type setup. But that is just the way that i see things. Just remember that this will be a first of its kind intro. I would love a 401K setup with an ether backbone knowing that i need to lock up funds for a period and still come out with the list price + interest at the end.