From what I've read, the hard part isn't cloning, we already have that technology. The hard part is growing it in a womb, where the baby is bathed in various chemicals at various times in its progression, and where the temperature has to be exactly right. Where do you attach the umbilical cord?
Do you know what the body temperature of the womb a pregnant mammoth is? Tough question.
Unless we figure out a way to make artificial wombs, our best bet is just to use an elephant for that. Since mammoths are unlikely to differ much in terms of body temperature and nutrient requirements, the problems you mention won't be much of an issue.
More problematic would be immune system incompatibility, which could lead to the mammoth or its elephant mother being killed by the other's immune system response. But I think we have a way to deal with that when it happens in humans, so there should be a workaround.
Anyway, first you need to get some cells with mammoth DNA to divide often enough. Before you have that, those other problems don't really matter much.
Could you point me to where specifically you have read that? Every article I can find on the internet seems to assume that using an Asian elephant as the surrogate mother will be as easy (i.e. very hard) as if we had living mammoths to carry the clone.
I sent an email to the team at MIT back in 1997 when the mammoth clone news first started hitting the rounds (maybe it's older, I don't know).
Even getting a hybrid asian/african elephant baby to survive is very difficult. How big would a mammoth baby be at birth? Could it even fit in the womb?
All that said, if someone does manage to clone mammoths, that will be very cool.
Do you know what the body temperature of the womb a pregnant mammoth is? Tough question.