If your question is strictly about the costs you've incurred so far, then my answer would be no
Regardless of the lien, the inspector and appraiser performed a service and they were paid for it. This is the same as if the inspection uncovered something that caused you to back out of the deal or if the home failed to appraise for the purchase price. That doesn't change the fact that they did their job. And it's irrelevant whether the purchase closes or not.
As far as trying to get the sellers to re-imburse you, you can ask but I certainly wouldn't expect to get anywhere with it. First of all, the appraisal and inspection are for your benefit only and the seller didn't require you to get these, they gave you the option to at your expense (although your lender would have required it. Besides, if they can't pay their taxes I'm sure you won't have any luck collecting.
As the others said, you should wait and see how it plays out and pursue ways to make the closing happen. If it all falls apart at the end, then you may be able to pursue them for damages if you can prove they made a blatantly false representation to you. But tax liens are not generally referenced in writing anywhere in the purchase agreement and are likely not discovered until the title search is conducted, so I'm not sure how much of a basis for a lawsuit you would have. That would be a question for a lawyer.
People spend money on inspections and appraisals all the time where the deal does not close for whatever reason. It's a cost of doing business and you may just have to chalk it up as a loss.
I wish you good luck though!