Kerri,
Since you asked, I will try to imagine myself in your situation and offer my opinions.
First, take an inventory of what you have already, and make a list of your preferences and priorities.
The operative word where space is at a premium is VERASTILITY.
Plan on having at least enough panties to be able to wear a clean pair each day between laundry days, at a bare minumum

. Bras can usually be worn more than once between washings. Don't forget to save storage room for your breast forms.
Camisoles and half slips can be more versatile than full slips, especially if you prefer varied height hemlines. The camisoles can also be used in layering.
Hosiery is a personal preference. I love gartered stockings. They take up less storage room than pantyhose. I usually get a pack of 3 pairs so if one leg runs, it's not a total disaster - save the good one, open up a new pair, and I already have a replacement ready when one of them goes bad. This principle can also apply to thigh high and knee high stockings.
Foundation garments are another personal preference. My preference is open bottom girdles. I can wear panties under them so they can go several wearings between washings. They hold my stockings up and my stomach in.
Another, more versatile choice is waist cinchers - at least one with removable garters if you are so inclined. Combine 2 waist cinchers, one low, one high, add a regular bra, and you can have the shaping effect of an all in one body briefer.
For tops, skirts, dresses, and accessories think versatility and harmonizing pieces. Two piece dresses can also be used as separates to mix and match with other items.
Accessories such as jewelry (earrings, necklaces, bracelets, pins), scarfs, and purses can provide variety.
If you are going to have only a few pairs of women's shoes, choose the styles and colors carefully so they will go well with everything else.
I personally don't wear makeup very often, so I will not make any suggestions on that.
Whew, I really turned that into an essay question!
I hope you find some of my ramblings useful.
Jadeanne