About the 4/5, it did happened to me. I suspected it had something to do with my inventory that was without empty slots. So I recycled one item and played again. Them it sucessfully completed. I hope this may help those who are facing the same problem.
Edit: Editing just to don't make a new post. The diffrence between suits is really only cosmetic? If that is the case, it seens not worth to pay 350k of dilithium on a item that doesn't give nothing in return (other than it is a bit more shiny) . so, unless it gaves you some advantage, I would suggest cryptic to lower the price of it, because otherwise, almost no one will be going to buy them (okay, there is always those who have no lobes for business and will pay that amount. But it will be VERY feel people).