@CJB: Thank you for another useful link. I'll check them all
@Green7: Thank you for the interest. I am also doing this on my free time just after the work and before my wife's orders
Quote: "I need inspiration and ideas. is it more pre-rendered or hand drawn, or pixel art?"
It can be anything it is more convenient for you. I am not fun of the pixel art, I really enjoy vector style graphics (Inkscape, Corel Draw etc.).
It is not necessary to be historically accurate. It would be nice to give a glimpse of humor.
Quote: "If you could tell me about how many sprites you need, stills and animated, how complex the animations should be, so i can guess the overall workload."
I can give the info that you need, so please tell my how would you like them, via e-mail or via this forum? On a second thought if we do it using the forum maybe we could attract some more helpers/ideas. Since the game is in top down view I don't think that the animations should be complicated: It is up to your choice
The following picture is a sample of what I have already made using Inkscape:
Take a look at the following pictures I found in the web that shows the style I have in my mind: