Can Paypal debit money from your bank account or credit card without permission, if you have removed it from your account, and your remaining added account(s) do not have sufficient funds to recover debts involved during disputes?

Yes they can. You can "remove" a bank account or credit card from your paypal account but that does not mean that paypal deletes that information. In fact paypal keeps all information you have ever given to them forever.
THe only way to protect yourself from this is to close any bank accounts and cancel any credit cards you do not want paypal to have access to.

Paypal took money out of my personal checking account causing it to overdraft leaving me with a negative account balance and overdraft fees and NSF fees. Oh and of course the scamming buyer that set me up claiming Item was not as described kept the item. Never returned it to me.

maybe... usually they give themselves persmission to draw blood in those "i accept terms and conditions"

They Can.
They Do.
They Suck.

They can, but you can always call your bank and tell them you did not authorize the transaction.

Don't stand for this [crap]!!!! If you did not give explicit consent to PayPal to take that specific sum from your account, you did not authorize the transaction. Let your bank know about this. Normally, the bank will refund you the money and reverse the overdraft fees.