Okay, as they are they won't make the cut, but you're really not that far off. Actually your drawings are very similar to how mine were when I first started out. Your style is solid and you should have no problems getting your work up to scratch.
So a few tips:
1) Draw your characters at around 3 times the size they are now, and shrink them when you're done. If working specifically for SC take an existing character, copy and paste it into paint and as soon as you paste hit ctrl-w to open the stretch menu and stretch both horizontal and vertical to 400%. That will give you the size to work in.
2) Always draw with the thickest lines in paint (5 pixels). This won't be a problem if you're working in a larger size.
3) Shrink your images using irfanview (free image editor).
4) Make sure your lines are smooth and there are no pixels in odd places. This takes a bit of practice, but it's worth getting right.
5) Shade your images.
I threw together a rough diagram of the sort of stuff you can do. It's not exact, but you should get the idea (re-used the left side of the body for the right, left out some details, etc...)
The final version is in the bottom right and shows the effect of shrinking (this works better if you start with a larger image too).
If you save this to your PC you can open in paint and then zoom in and see exactly what I've done pixel by pixel. I made sure that every line I put in is a different colour so you can tell them apart, I just re-coloured them when I was done.
Step 2) is the outlining process
Step 3) is the colouring. Note that the pockets are slightly darker than the jacket to make them stand out. I also took out the lower pockets as I forgot to outline one.
Step 4) is the shade outline. In Step 5) I coloured all the parts I wanted to shade according to the outline.
Step 6) is everything that isn't getting shaded
Step 7) is step 3 but darkened in Irfanview.
Step 8) is step 6) pasted onto step 7).
Step 9) is the final version, though I forgot to remove the shading between his arms and body ;)
And yeah, in regards to submissions I very much doubt Brad will take anything that's already represented on the site, so get some practice in and see what you can come up with :)
Dinosaurs had eggs bro, the chicken came way later.