Very lovely tank! It's always nice to see the progression of a big project like yours.
As far as adding angelfish to your tank, they should be fine with your current stocking, save the serpaes and shrimp. Serpaes can be nippy with long-finned fish, but will usually be more mild-mannered towards other tankmates and focus their slight aggression on one another in a large enough group of six or more. I have, however, heard others say that serpaes can still chase, nip and basically stress slow moving/long-finned fish no matter how many other serpaes there are in the school, and angels are definitely classified as slow moving and long-finned. Juvenile angels are especially sensitive in community tanks and can be easily outcompeted for food and territory and can die from too much stress caused by other fish chasing and nipping.
Looks like you have an amano shrimp from the last set of pics you posted and amanos grow to 2", so your angels may never be able to eat your shrimp. Angels usually do harass most inverts though (shrimp, snails, etc.), to death in most cases, so keep that in mind as well.