Pman,
The shorter deck height will not hurt anything. Sometimes it makes it harder to find pistons to work with a particular combination, but since your short block is already done, you should have no worries.
The girdle/pan clearance will depend on what pan you go with. I did a 425W with a Probe main girdle and a Canton T-sump
oil pan. That particular combo required that I dimple the
oil pan out in a certain area so the girdle would clear. I did a 347 a few months ago with a DSS girdle and a Canton pan and it didn't require anything. So it just depends on the combo.
I think you'd be fine to just put the parts on the 408. The 195cc is a little small for my liking on an engine that size, but if they flow well, it should offer good port velocity and throttle response for a street cruiser.