I don't pre-wash unless it is flannel (and that depends on the project). If I think a fabric might bleed, I test it by placing a piece in a glass of water and leaving it for a day. If I see wisps of dye in the water I will prewash. If no wisps, then I take the damp fabric and rub it against a light-colored fabric to see if the dye transfers that way.
Shrinkage (except sometimes for flannel) is really not an issue if the sandwich will be moderately quilted. Once quilted, batting will control shrinkage. In other words, a fabric will not be able to shrink more than the battng allows. Shrinkage *is* an issue for plain fabric (for example, a dress) and for tied quilts (especially if ties are far apart). In these cases, there is nothing to prevent the fabric from shrinking to its max.
Bleeding is more of an issue. I handle this by taking the precaution of doing the first wash of any quilt in a washing machine that uses ***lots*** of water (to dilute any dye bleeds), and by using Synthrapol in that first wash (suspends unset dye particles so they stay in the rinse water rather than settling into fabrics). The only type of bleed this will not be adequate for is a bleeding fabric -- that is, one where the manufacturer did not set dyes properly, so that the dyes will continue to bleed with every wash.
Have to run..... Maybe more later.