Bankruptcy Law Questions? Ask a Bankruptcy Lawyer.
You're better off to keep the lease and just re-affirm the debt along with all of the other debts you're planning to repay - if you want to keep the truck.
The reason your attorney wants you to purchase a cheap vehicle is because creditors won't come after it and you won't have a car payment complicating the repayment matrix your attorney and the trustee will agree upon.
Your chances of getting financing are better if you pay out the lease instead of letting it go early. If you give the vehicle back, you're ceartinly not going to get financing.
You're right that you can keep your property by filing a Chapter 13. It is a reorganization of debt into a payment plan that you can pay monthly for 3-5 years, depending on the amount of debt, income and assets you have.
My best advice is that you try to agree with your attorney on how to proceed before you do anything. It may be that you can work something out where your retirement money is not in jeopardy of being thrown into the bankruptcy estate by buying the truck. As you probably know, retirement accounts are usually safe in bankruptcies and cannot be used to pay off debt.
Also, you don't want to do anything that may put your bankruptcy in jeopardy of being dismissed. It is worth sitting down with your attorney and trying to evaluate all factors before you go out and drain your retirement account for a new vehicle.
My guess is that your attorney wants the plan to be put in place by the court before you do anything. At that point, it would probably be easier to dip into your retirement money and get a new vehicle.