All have been previously discussed here or there on WildblueWorld.com Forums.
1. Not right away. I would guess six weeks to three months for commissioning.
2. No. Nothing will change for existing accounts immediately. Depending on marketing/migrating policies, the load on the existing satellites/spot beams may go down and that may marginally improve speeds on accounts heavily affected by loading.
3. There are a number of components of latency ("lag"). The largest is fixed by the location of geosynchronous orbit and lightspeed. Another, the terrestrial internet 'circuit' is not under WB's control. A third, WB's Demand Assigned Multiple Access DAMA protocol is under their control somewhat, but cannot go away until we get individual spot beams.
4. The speculation has been of the same pricing structure. That must be balanced with the declining real value of the dollar and ViaSat/WB's participation in international commerce. The US$ dollar has to compete with world currency values.
Forum defenestrator and not a Wildblue employee. Good people ought to be armed as they will, with wits and Guns and the Truth.