Right now it looks like this...
I have a sprite with 4 points on it one on the top,left,right, and bottom (this part is the main part I'm not sure about should I be checking just these 4 points or the whole line of the collision box?)
Top, bottom, left, and right? Do you mean at the four corners or do you mean like the first figure in this?
Because that would cause major problems.
If you're not worried about computing power, go with the line check. It's just as easy to check a line between two points as it is to check for multiple points on a line.
Personally, I've always just used a collision mask for my sprites, like in the second figure, and checked for overlap that way. It takes up even more processing, but it's easier to check for small things like bullets. It all depends on what you need your engine to do I guess.