Maybe I missed it but is this job a one-off, small series or larger series production? Your speed/feed/bit size optimization strategy may depend, also how you hold it down. For small quantity the tabs may be O.K. and the feed etc. is not that critical because you will spend anyway more time preparing and finishing. But for larger quantity of all the little blocks I would probably drill/mill the holes first and make a custom fixture with suitable dowels to hold the parts for the cutout (downcut bit) without tabs.
As for the final product, you may have to somehow chamfer the sharp edges or they could leave unwanted patterns or splinters on users' posterior.