You can select as many as you like - just increase your pledge as appropriate. For example, if you're at the Advanced Warfare reward ($125) and want a second one, just pledge a total of $250 - you can tell us that this is what you want at the end.
If you're at an Early Bird level, then any additional reward levels of the same type will be at the same cost, so if your first one is costing you $115, then the second one will cost the same price!
The customs form on your package will be marked with the value of the contents exactly as listed on Kickstarter, with no exceptions. For example, if you have pledged at the Advanced Warfare level ($125) and selected no add-ons, your package will be marked with a value of $150. If you had also selected add-ons to the value of $50 over and above your pledge level, the package would be marked with a value of $175.
The cost of shipping will not be included in the value marked on the customs form. The package will also be marked as a gift.
Please check with your local customs office for any charges that may apply to your shipment as you will be responsible for these.
Here at Mantic we don't want to release figures through Kickstarter that will then penalise customers who miss out on the campaign. However, we do want to keep our Kickstarter exclusives a little bit special. Therefore, although our exclusive releases will never be sold at retail, they will be available later via the Mantic Points Scheme on our website, or offered as promotional figures at conventions that we attend.
In the case of the exclusive heroes available in the Warpath Kickstarter, it is these specific poses that are Kickstarter exclusive - when it comes to releasing the model at retail we will launch an alternately posed version of the character, with optional parts to make a generic hero of that type (Forward Observer/Forge Lord/etc).
Don't see the answer to your question? Ask the project creator directly.