Who files Form SS-4?

The number is not tied to having staff. It is the employer identification number an entity uses to identify itself for US filing and withholding purposes, and a new US entity generally needs one before it can file anything at all. Payroll is only one of the uses. A bank will usually ask for it, and any withholding or information return the entity has to make is identified by it. If the entity exists and has US obligations, treat the number as a formation step rather than a hiring step.

It can. The test is the obligation, not the address. A foreign entity that has US withholding or filing duties needs a number to make those filings, and so does a foreign-owned limited liability company that has information returns to make. A nil position does not remove the requirement, because the duty is decided by what the entity does and receives rather than by tax owing. Work out which US filings the entity is on the hook for first, because the answer to the number question follows from that list.

Yes, but not by the fast route. The quick application that issues a number in one sitting expects the person responsible for the entity to hold a US social security number, so a foreign applicant is left with the slower channel. That matters for planning rather than for eligibility. The number is what the bank account, the payroll registration and the withholding filings all depend on, so for a foreign-owned structure it becomes the first scheduling constraint of the whole expansion. Start it before the dates that depend on it are promised to anyone.

The application asks for an individual, not simply the corporate owner, and it wants someone with real authority over the entity's funds and assets. For a foreign-owned structure that is usually a director or officer of the parent rather than a local adviser. Two practical points follow. The person named needs identifying details the application will accept, and the name given should match what the bank later sees, because a mismatch between the number's own record and the account opening documents is a common source of delay.

A foreign-owned limited liability company that has information returns to make needs a number of its own in order to make them, even where the company itself pays no tax. The point people miss is that the filing duty sits on the company as a separate filer, so the owner's own tax number does not stand in for it. If you are unsure which returns apply, list the payments the company makes and receives and who reports them. The number follows the filing obligation rather than the profit.

The application creates a number for an entity, so the question is whether the thing doing the filing is the same entity. A new US company formed in a restructuring is a new filer and needs its own number. A change of name, address or responsible person for a company that continues is a change to an existing record rather than a fresh application. Get this right early. Filings made under the wrong number are hard to unpick afterwards, and the bank and payroll records will both have been set up against whichever number you used.

Sending your own funds to India is a transfer of capital, not income, so the remittance itself is not taxed. What is taxable is income the money then earns in India — interest, rent, capital gains — under the rules for the account type it sits in. Sending money out of India is the direction that needs certification before the bank will act. See NRE, NRO and FCNR accounts.

In this order. Fix your residence under each country's own rules, and if both claim you, apply the treaty tie-breaker. Identify where each type of income is sourced. Read the article that covers that income type, because it decides who taxes and at what maximum rate. Then claim the relief on the residence-country return, with proof of the foreign tax. Most of the tax people lose to double taxation is lost at the last step, not the first. See how double taxation is relieved.