So for starters I hate 2 level islands i think they are a waste of counter space but if you insist Ikea has awesome butcher block counters and they also have a set of attachments to install on the counter that lets you have a raised bar with a different counter. As for the garbage hole you will regret that decision very quickly when the stink from the garbage comes up through the hole , no matter how picky you are. and the edges of the hole get filthy all the time. I have had Ikea butcher block counters in my last 2 houses one is 17 yrs. old the other 7 and both look like new. Pic is the attachment from Ikea

Great info. I guess I'd definitely drop the garbage chute. Didn't think about it that way.

Good idea for the hole in the top! We would suggest using an epoxy resin on the rim if you do a cut out. Keep in mind, your prep station will most likely be edge grain butcher block. Great for a prep station but you wouldn't want to cut or chop on your nice counter top. We would suggest getting an end grain chopping block made with some handles you could use as a cover for your hole and lift off when you want to put your trash through the hole. Hope this helps!