I was thinking about using the fondant that is already precolored and prepackaged from Michaels. I think it's wilton, it's 4 different colors, and I believe it's Wilton.

This is be used for flowers and butterflies on some cupcakes, not really meant to be eaten, although, I'm sure some will. But it's the cheapest, especially with a 50% off coupon

How well will this dry out? How soon in advance should I made what I need?
Will I need to mix it with gum paste or will it dry and hold it's shape?
And fyi this is will be a birthday party with mostly adults, and some kids, so In case some were to eat them.

I haven't tried the Wilton brand fondant. I have heard that it does not have a good taste. I have bought Duff's fondant and that is very easy to work with and has good flavor. I would make any figures or decorations at least a day or two in advance to allow for drying time. Fondant doesn't usually dry completely hard, so you might want to add some tylose to it if needed. I hope that helps!

I use Wilton a lot. I know there are people that say it doesn't taste good, but there are also people that have tried it and haven't had any issues with the taste. You can also flavor it, but for small decorations I'm not sure I would actually bother with that.

I have used Duff's fondant recently for cut outs to go on a cake, and I would not use it for anything I needed to dry hard. It was very soft and very stretchy. I also know someone that has tried to use it for bows with no luck.

Wilton's fondant will harden up. It will take longer with out anything added to it, but it is possible. Are the flowers and butterflies something you want to lay flat on the cake or hold their shape away from the cake? If you want them to hold their shape I'd do the straight fondant probably 4 or more days ahead of time. You can also add gumpaste or gum tex to it to help it dry faster.

I agree with TexasSugar. I have both Wilton and Satin Ice here. I like the taste of Wilton way more than Satin Ice. IMO, SI has a playdoh sugary taste to it.

I mix my Wilton fondant with gumpaste and it dries much faster and harder than just fondant alone. I use a 50/50 combination.

I have used Satin Ice and Wilton's. I prefer the Wilton's for decorations. the taste is so so ( I like buttercream better) but by golley wilton's fondant will stiffen and cover!!! I love the 4 packs of colour. This seems to me a drier fondant so sometimes I add crisco and always keep it covered when not working with it. I added some Wilton's fondant to homemade fondant for a wedding cake when the homemade just stretched. It really helped the problem. Have heard that you can add flavour to it but if it's just small decorations don't bother.
Do add some gumpaste to fondant to help stiffen your decorations and flowers, especially with this humidity now in summer.