Of course you can use 2 vehicles in your business at the same time and for each vehicle you have the choice to use either the Actual Expenses or the Standard deduction method ... both do not need to be the same.
And you do not need to "buy" the car from your wife ... simply convert it to business use. Since you are not buying a new vehicle you cannot take the bonus depreciation (buying from family doesn't count) so your idea is flawed.
