How long does fondant and modeling chocolate stay good once sculpted? Not covering a cake, but as figures etc.  How many days?

I know that fondant last for a long time.  I do not know about modeling chocalate since I do not use it.

Thanks!

If you can keep bugs away fondant &/or gp  will last for many, many years.  Choco/modeling paste is a different matter.  It draw bugs (depending on where you live) faster and is more touchy to heat.  Choco also will develop a dusty taste after just a few days.  Hope that helps. 

Thanks! 

How far in advance could I make the modeling chocolate one do you think? 4 days?

I have no experien ce w/ modeling choco but from what I have read on here yes, that would be about the limit.  Keep it stored in a cool, dark place, best if  in a cake box or similar.