In my personal experience, it was not necessary to do a final estate tax return for my Mom - the size of her estate was not large enough to cause "final" returns to be done. However, the Court Appointed Administrator (my brother was Executor but unfortunately passed before Mom's estate was finalized) wasted $500 just because he wanted one done.
My husband was Mom's CPA for over 20+ years and even informed the Administrator! Then the Administrator wanted to do 1099's or K-1's - totally unnecessary - he had no idea what he was doing! He wouldn't even allow my husband to do my Mother's Final Tax Returns at no charge (as he always did for Mom)! He hired another accountant (don't know if he was a CPA or not) but we didn't get a chance to even look at Mom's Final Tax Returns! He even had the nerve to tell me "he didn't have to be accountable". He will be!!
The best advice I could give you if you do not have or know of a CPA, call the Department of Revenue of your state. Ask for the "details in closing an Estate", ask if they have a "checklist", and finally, ask what the "qualifications" of the size of the estate and if it is necessary to file "final" state/city tax returns for the estate.
It sounds like with you or your sibling still have yet to get the "legal rights" - hung up in Probate Court? Or is there another sibling questioning the Will? Either way, remember the funeral home notified Social Security of your Mother's passing in August 2007. My Mom passed in May 2005 and I'm still in Court! I'm like you, there are too many "attorneys with their own agenda's and can't get any straight answers out of any of them" regardless of my Mother's Will!
Property tax is different issue. Regardless of whose name the estate is in - there will always be property tax to be paid. Once you and your sibling finally are awarded the estate, immediately get the name change done - you will need a death certificate, the Court Order giving the names the Estate is in, and probably more forms (call the State Treasurer for property tax). Perhaps you can get the forms sent to you in order to get things prepared so you are ready to take action when the time comes!
Hope that helps. Sending hugs & prayers - I know how difficult it is to deal with this for such a long time. Like I said, my Mother passed in May 2005 and I'm still having to deal with it!