That is enough room for safety, but not enough room if you envision prepping beside the range. You will do your prep with your back turned to the cooking zone, adjacent to whatever sink is there. If you want to prep facing the seated persons, then you would need to move the range to a wall location, leaving the island free. In addition, a 58" island is an awkward depth, disproportionate to the 80" of width.Post a layout of the actual space under consideration to the Kitchen Forum in order to get the most optimum use of the room.

We are both reasonably short, (5'4" and 5'6") but I have mine at 35" above the surface. The higher they are, the more light they cast. Also, if they are clear, you want them high enough so the light doesn't hit your eye so directly. Also, your guests may not be as short as you. Unlike a dining table, you are frequently reaching forward over an island to clean or grab something, and you don't want to be hitting your head on the light, as may often happen at a DR table where it's 30" above the surface.

I can't tell without measuring it but I think Sophie is correct. One slab for the island, one for the prep areas and one for either side of the stove. If you will allow them to kluge together the prep areas with scraps from the stove slab you may be able to get it out of the same slab as the stove but you may never be what happy with how it will look. You should do a little research on templating (sorry, I know you're probably up to your eyeballs in things you really don't want to know about) and you really need to be at the templating.

Without a water source, prepping on an island or peninsula usually doesn't happen much - no matter what you "plan". In my old Kitchen, I had a 36" piece of counter that was not near the sink that I never used and, instead, used the 24" b/w the sink and range. I needed water to prep and it was much easier to stick to the 24" of counter than to keep moving things back & forth. We have heard similar stories over and over here. . Regarding barrier islands not being in the way - yes, they are. *** Warning - what I am about to say may offend some people. I don't mean to offend, but I want to be sure others reading this understand. *** Some people won't admit it's an issue running around an island or maybe they don't realize how much they're running around the island until they take the island out. My SIL always told me that she was OK with a barrier island - UNTIL she remodeled. She took out the island (with no sink) and intended to put another one in later - but she finally admitted to me that she would much rather have a lot of open floor space than put an island back in. She didn't want to admit originally that she had made a mistake (so typical of us humans!), but now is willing to admit it and says there is no way an island is going back! She is so happy that she doesn't have to run around that island over and over - and it really wasn't all that big an island - only 42"W x 35"D. BTW...she doesn't have much prep space b/w the range & sink, but always used it anyway b/c, like me, it was easier than moving things back & forth. I think she has about 18" b/w the sink & corner and another 18" b/w the range and corner - that's it. Even when she had the island it was much easier to use the counter b/w the sink and range. I couldn't talk her out of having the sink under the window - that's why she as so little prep space in the remodeled Kitchen. :-(