Most of the questions I'm seeing would appear to be more issues of practicality than of ethics. Clone a neanderthal or an extinct species requires potentially also cloning extinct food sources for those species, unless current day alternatives would suffice. Yet you wouldn't know that for sure until the cloning had already taken place and a viable specimen is at your feet.
If cloning an extinct species is to be useful, then these considerations would obviously have to be taken into account. No sense cloning an extinct species, only to have it die within weeks as there are no viable food sources / habitats for them.
I think any cloning undertaken, should have a specified goal. We've cloned extinct species A because we wish to answer questions B and C. There should be a scientific purpose behind cloning, rather than just cloning stuff for the sake of cloning it. Again, I see this not from an ethical stand-point, but one of practicality.
"Look we spent time and money cloning a Dodo."
"Excellent, what burning scientific questions have we gained insight into as a result?"
"Uhhh....hey look, we named it Frank."
To my mind, cloning an entire viable community of an extinct species is far more worrisome than cloning a single specimen. You now have an extinct species, re-introduced to a changed environment, and you must now commit to caring and growing that community....to what end result? To what consequence?
I don't think any of these scenario's is hands down unethical. I think it depends on the consequences, and the considerations and goals laid out as justification for the cloning of a species.
