I like that Sony multi-media player---very clever way to add a larger screen in a single-DIN opening.
The total weight is important only when/if you're build will be extensive or add a lot to the vehicle's total. As long as you don't exceed the GVW you'll be okay suspension-wise. Your E150 is rated for 8,600# right?
My concerns were more towards the engine because the 4.6's are a bit down on power as they approach the upper limits of the GVWR.
Empty weight gives you a base line which most likely will be useful once your build is completed AND again when your van is loaded for a typical trip. Not for nothing but my '05 E350 extended body with raised roof weighs just at 6,200# as delivered, it now weighs a whopping 8,400#---I've done a few suspension upgrades along with adding Hellwig anti-sway bars front and rear, adding an extra leaf to the rear springs and use Bilstein short wheelbase motor home shocks---load control is my goal.
Find a close-by CAT scale and they'll be more than glad showing you how to measure the front and rear axles separately---its simply a matter of where you park on the scale. Here's a link: https://catscale.com/cat-scale-locator/