I would like to write a story featuring creatures living in a ecosystem not unlike the one we know, but still they are alien creatures. I would like the details of these creatures' functioning to be as scientifically sound as possible.
Would it be ok to ask questions like
Given the size of the animal and their species, how much would they weight? How much blood would they have? What should the caloric value of their diet be?
If those kinds of questions would not be appropriate to Biology StackExchange, how could I rephrase them so that they would be?