Some Basic Questions.

Alright, i have a little foresty area in my backyard, ive cleared about 3 spots where i can throw a few plants but the thing is its really hard soil, if i dig a ddeep enough hole will it even matter? Should i use some mulch? And can i use soil thats been in bags that sat outside all winter?

Dig deep and wide if you want, at least 1 x 1 x 1, yes bigger is better. You can use all the black dirt you remove from the hole and some of the other soils you remove.
Dig and fill the holes to allow microbial activity to begin, The early spring soil is lacking warmth to promote proper root grow. Maintain in buckets or pots large enough to hold untill transplant into the holes, once the soil warms up. About a gallon per foot in height.
The the soil will work out just fine, add some worm compost if you can. Worm compost has an advantage over pure worm casting, it contains worm coccoon too. Mulch with composted manure, this will work as a water retaining material, and add nutrients. Coccoon will hatch, reproduce, eat manure and deposit worm castings.
If you tell nobody and nobody knows, you can use this well dug and fertilzed year after year. To maintain a worm population cover area below plant with aged manure for mulch.