Try the guys at theprintful.com they have made a good niche business providing the services you seem to be needing. Best of luck, learn from them and keep asking questions ;)
A good starting point for determining valuation is 3x your annual profits. That said, you may find a 1 - 2X variance up or down depending on the type of product(s), the category or categories you sell in, your total number of SKUs, etc.
There's no "reliable" way to do this, as you're interacting with one or more shippers. After shipping physical product around the world since... 2003... every shipper only gives ballpark windows of when they can complete a delivery. Using Amazon FBA will likely provide fastest delivery times.
I would say you have a few options, message me if you want to chat about it in detail.
If its for sales through Amazon (or even elsewhere) FBAPrep.com is one of the best out there. They can handle importing, preparation (repackaging, barcoding, etc.) and then final shipment. Plus, they know the special requirements of Amazon and other third party marketplaces.
You're already saving by using a fulfillment house in each region. You could save a little more on costs by sending the product to the 3PL already picked and packed. If your product is repacked in a mail-ready package that will save some. You could take that one further and send the picked, packe...
If you've done a great job setting up your business, I believe your net profit will be something like $.60 to $1.xx per package you process and ship.
These are all specific questions you need to be taking to a Tax attorney, or accountant. The laws are varied on all of your issues and need to come from one of the places I just suggestied, and not from a get help site. Good luck