you can use all of those fabrics-and more if you want to- they will make a beautiful crazy quilt. as for laundering/care---if you can wash the fabrics individually you can wash them later---gently- most crazy quilts are actually just vacuumed if they become dusty- it would depend on the use- you could have it dry cleaned- but would really want to know the cleaners---items like this have mysteriously disappeared from cleaners---or been ruined- mine i used all of the fabrics you mentioned along with suedes, satins, vietnamese silks...wools- and used alot of silk embroidery flosses- and ribbons- beads and buttons- i washed everything before i used it- anything that did not live through that-did not make it into the quilt- it has been gently washed in cool water a couple times in its life- the back is a satin brocade.
as for the foundation- it sure makes the piecing/embellishing easier when you have a foundation- the foundation keeps everything stable-keeps fraying of edges under control= but it is a choice-not a requirement- i embellished mine in blocks- then joined the blocks- and embellished more-the joining seams- using a muslin foundation- i could just cut a piece of muslin the size i wanted= then start sewing fabric pieces to it- along with antique laces- and trims- and (play) work on that block until i was ready to move on to a different one...some were rectangular- long and narrow- some were square- as i finished each block i would add it to the design wall- some of them hung out for months- sometimes i would spend an hour or more just moving them around- perhaps creating a hole that i would need to fill- giving me the size/shape of the next block- i would send pictures- but gave the quilt to my youngest brother for a wedding gift 12 years ago---the pictures have been gone for a long time---2 or 3 computer's ago==
anyway- don't be afraid of it- once you make that first block- even if you decide to wait until it's a quilt to embellish you will find the process so---enjoyable! i even used stablizer and machine embroidered flowers on some of the silks-they are FABULOUS!!!
maybe you should use some scraps of regular cottons and make a couple (practice blocks) one with foundation- one with out---and see which technique you like better- i will tell you---it is easier to use different shapes (sharp points-odd shapes) with a foundation.
as for what is a good size???that depends on what you want it for- my brother and his wife had just purchased this wonderful overstuffed leather furniture and i decided one to fit over the back of the sofa would be wonderful! and it is!!! i don't think i would have wanted to make it bigger- by then i was quite tired of working on it and ready to move on-but i've made a wool crazy quilt that is queen sized- that one also is extensively embellished- felted wools- no foundations- the felted wool was stable enough on it s own-and i was not mixing fabrics other than adding laces/trims.