I was trying to add the metrics entries, exits and single page visits in data warehouse but cannot seem to find them anywhere. I'm not sure if these should be available in DW but I tied looking under both Standard Items and Custom Insight metrics with no luck.
I'm not sure if this is due to Adobe introducing the dimension but there is a dimension called "Clicks to page" which you can use as a dimension to see where it's equal to 1 and therefore an entry. It appears you can also segment on this but it's called something different "Visit page number" so you can run a Data Warehouse request either with "Clicks to page" as a dimension to see all dimensions where "Clicks to page" is equal to 1 or create a segment where "Visit page number" is equal to 1 and apply that to your request.
Obviously this can't be used as a metric so slightly annoying as you can't have visits and entries to get entry rate but you can either use the dimension and do the sum of visits by those where "Clicks to page" is equal to 1 or run two separate requests one with the segment applied and one without.
You can also do something similar using "Path Length" for bounces and bounce rate.
Unfortunately I haven't found a solution for exits / exit rate.