I live in New Zealand and I am looking to start an online website sourcing and selling products within the USA via drop-shipping methods. This part of the process is underway. However, I understand I need to set up an LLC, get an EIN, an ITIN, a merchant bank account and from what I've researched to date, the general consensus is to set up my LLC in Delaware.
I would really appreciate some advice from anyone with experience (personal or professional) in this area. There are companies who offer 'package deals' covering these things, are they the best way to go? Is there anything else I'll require to start-up? Are there any pitfalls I may not be aware of?
You don't necessarily need to do any of those things except comply with the US tax authority's rules for getting their money to them (which might be an ITIN if you operate as an individual, or and EIN if you are operating as a business).
The simple fact is that you do need some measure of specific advice about what exactly it is that you're planning, the tax consequences of that activity, and what business structure, if any, is most suited for your mix of circumstances.
The US is vastly less regulated on the "starting a business" axis than any other country I've worked with. It is possible for a foreign national to just go ahead and start doing business, as an individual, with a minor number of administrative hurdles. Depending on your operations, you may need to register to do business in one or more states, but even that's not necessarily clear from your limited description.
You should spend a few hundred dollars to get specific legal advice relevant to your specific plans. It may be that you have to do almost none of these things you describe.