It would be nice to order from one place to save on shipping!
Probably the most heard sentence on any DIY effects message board! FWIW, I have substitued the mica caps for the ceramic many times with no ill effects noticed. They are more expensive than cermaics but you make up for it in the savings in shipping. Rat Shcak does sell some ceramics but their selection is limited. You might be able to get the value that you need in their grab bag that they sell, but if you can just substitue a mica, why not do it? You also might get the grab bag ond not get what you need, since they do not have any pre assigned values that are supposed to be included. I can see no difference between the two varieties that would cause any change in tone.
Another thing to consider whnordering from Small Bear is the price that they have on 3pdt switches that we all use. You can order one switch from Pedal Parts Plus and even with shipping (at least for me) it is still cheaper than the price at Small Bear. I love using Small Bear because they are about the closest thing to a one stop shop that there is but the prices on those switches are over twice what everyone else sells them for.