If registered in Texas, I don’t think you can take out the tax amount. Even if transferred out of state. So anyone would have to add local taxes to that.
In TX you pay sales tax on the value of the car when you sign the lease but in return you have no tax on each lease payment. So each lease payment (including taxes) if the car remains in TX would be $599.84/mo. If the car is transferred to another state, tax and total payment amount would depend on the rules of the new state.
Yes. In most states (that I am aware of) that tax the monthly, they will add that states tax rate on top of the TX payment (which of course already had the tax in it). Robbery!
The application for registration is in BMW’s financial services vehicle trust name - so would not expect any change in title from a lease transfer and thus no additional taxes if the lease transfer is to someone in TX. So $599/mo (post-tax) for someone in TX.