My guess: if non-genetic heritable elements -- epigenetics (such as modifications to DNA) -- are necessary for proper development, then the DNA sequence alone will not be enough to develop thylacines. (There are caveats, notably that some modifications can be inferred). However, the scientists will also be experimenting with gestation and creating embryos from modified cells, so whether epigenetics specifically is a limiting factor will be hard to tell.
Yes, that was basically my point. There has also been some fairly fevered speculation about epigenetics being responsible for some types of instinct - even "cross-generational memories" and the like.
This is a really great point. I want very much their effort to succeed, but I suspect epigenetic is so important for higher organisms that the chances of this working are rather low.