Finding fossil microorganisms and observing that they look very similar to those found on Earth would be an indication to me that the rock may not be a meteorite after all, or that it may be a meteorite from Earth (i.e. blasted out into space by an impact, then fallen back to Earth some time later).
"There are some that are just very strange and don’t look like anything that I’ve been able to identify, and I’ve shown them to many other experts that have also come up stump."
makes me a little curious. I'm not a biologist, so someone who is, how often do you find organisms/fossils completely different from known organisms?
I'd imagine those would be very easy things to check. Per the article, the meteorite was identified as being an exceedingly rare (9 on earth. Total.) CI1 carbonaceous chondrite.
I suspect the claims will likely be debunked, but not for the reasons you gave.
