The inconsistencies can most likely be explained by the artistic process. Artists do not draw a page in one attempt---there are many steps. The common method I know of--and use myself--involves drawing a rough, then drawing each panel or component seperately before puting it back together and drawing the final. Each panel may be re-drawn several times to change or correct details. If Cassaday did indeed trace Wams drawing--and I think it's pretty clear he did--changes may have occured when he re-drew the the panel and eventually the final page on a lightbox.
Let me ask you this, just to see.
In the 70 years of Batman's existence.
In the 70 years of Batman art.
And the millions of people who drawn the character, professional and otherwise, how many times do you think a pose like that- which is classic- with Batman just ****ing standing there at an angle...has been done? Just, a round numer....a guess, if you will.
Okay, now- how about the chances that out of those billions of pieces- that some artists might draw based on reality, human bodies. That is, the character isn't exaggerated, not too muscular, but looks like kinda a real dude. How many do you think, along with the classic pose?
Okay, how about designs one the cape and trunks, and so on? There's not many different designs out there. DC Comics, once changing the Bob Kane and Bill Finger (Cheers, Batacot

) have basically kept his costume the same.
So, let's just say.....whatever you THINK is copied, are coincidence.
What are the chances of that, do you think?