I had some misinformation on here regarding women's dresses. I talked to Elizabeth Stewart Clark and she gave me some better info.
I've not come across anything to indicate that linen was used for women's dresses at the mid-century. Cotton replaced linen as a cheap dress fabric earlier in the century (1820s), and linen use by the 1840s is increasingly limited to chemises, drawers, some nightgowns, rare petticoats, and some personal accessories, as well as aprons. As an apron, linen is particularly advantageous--it doesn't sour as easily as cotton! So, if you want to use linen for summer wear, limit it to 100% linen for chemises, neckerchiefs, and possibly a tan/white linen apron check (1/4" gingham in 100% linen).
I can't recommend the linen/rayon blends. The rayon defeats the purpose of the linen. :)
Wool is appropriate in any season of the year. Sheer (seriously--transparent, read-a-book-through-it sheer!) wools are used for summer dresses, while wools marketed as "tropical" or "summer weight" today can be used three to four seasons of the year in many areas. Houndstooth, herringbone, and pinstripe wools should be avoided for mid-century dresses; look for plain solid colors, plaids, and checks.
[Stripes, checks, and plaids] can be pretty popular as patterns for dresses through the era! Print styles change a lot from 1846 to 1865; with a little study of original garments, though, as well as some key reference books, you can train your eye to choose from among repro cotton prints, and that opens the style options up a lot.
The "homespun" cloth in stores today is too rough for better daywear. As a lower working class dress, though, they can be useful.
Lace was not generally applied to cotton dresses. Instead, tiny amounts of true lace, or crochet/knit laces done in lace-weight threads, were applied to accessory items, like handkerchiefs, collars, cuffs, and undersleeves. This holds true for pairing lace with silk and wool dresses, too... it's not commonly applied right to the dress.
Unfortunately, most of the "crochet lace" used today is far, far too chunky and heavy to be useful in repro clothing.
[Pockets] are not common on dresses, however (those tend to use a pocket set into a seam near the side of the skirts). The separate dress pockets had a peak in popularity much earlier in the century, but by the 1840s, their use was essentially relegated to travel, and not to daily living.
Liz has more info on ladies' dresses on her site, as well as here.