For #2 - I don't think Starter Packs should be transferrable, they are Starter Packs and should not be sellable. Your initial concerns are valid.
For #5 - What about a 3-card pack for 2k DEC but an altered drop rate so it's not statistically better than the 5-card pack? Having a half-price option with a chance at a GFL is what I'm trying to accomplish. What do you think?