I'm currently moving from Australia to America to study at the University of Oregon - a strong sustainable program, so I have a good knowledge base to answer from.

1. Loans. Or money from family. Many banks offer student loans to foreigners as long as you have a US cosigner. 
2. Depends on your job. 40k approx for a grad student - all of your living expenses. Usually 10 years + interest.
3. Scholarships. Work study options. Unlikely though for an international student to be given such opportunities, normally go to domestic students. 
4. Why would you even consider doing a non-accredited degree? What a waste of time and money.
5. Can't tell you that one - presumably high. Look at their entry requirements online. English proficiency is high for US institutions. 
6. India you will look impressive with a US degree - however in the US you will need a professional, accredited M.Arch or B.Arch to be considered for work. 
7. Sustainable design is taught as a founding set of principles and ethics. You then use these principles within the variables presented in a site whether that be cold or humid and you design considering the environment. The schools use local sites as examples, but if you have a passion for it, and use sustainable design within the confines of your schemes - firms will acknowledge that your designs respond to the environment and thus, when one looks at you for a tropical job they will notice the attention to detail within your cold sustainable designs, not necessarily the fact you've not designed warm. It will be learning on the job.

Hope that helps. 
 

As an Indian student myself..

1. Returning to India and hoping to pay off your loans is difficult to say the least. Salaries are impossibly low even for those with a masters degree and some work-ex thrown in. However, a degree from a top-10 or a solid state school in the US can open doors in places like SE Asia and the Middle East, so you should consider those options in case the US visa/work situation doesn't work out. I have lived in the Middle East and can personally vouch that an American degree on your resume is looked at very positively.

2. Depends on your loan, your salary and how much you want to throw in each month. Key in some values on a repayment calculator and you'll get an idea. Keep in mind that Indian education loans have a cap of 35-50k USD and exorbitant interest rates of 11-12%. So plan for the rest of your funds (A 2 year masters degree will on an average set you back by about 80k).

3. Most Indian students I know either work as TAs or other on-campus jobs. Some of these come with tuition waivers, stipends etc. You should talk to students at your prospective universities to find out what the opportunities for international students are. I've known people to do some extreme cost cutting (three people sharing a bedroom kinda things), but I think its not worth being miserable for a couple thousand extra $$.

4. Accredited. Makes no sense to do a non-acc program unless your undergrad degree allows you to pursue licensure, which Indian degrees do not. Serious waste of money IMO.

5. Common sense tells me that work opportunities will be limited to none if you do not speak the language of the country you are in. 

6. I'd assume you will want to look for opportunities outside of India for the first few years, presumably until you pay off your loans. In this economy it would be wise to not take on crippling debt for a notoriously ill paying degree like architecture. A debt amount under what you would expect to make in your first year is usually recommended.

@Nick Weaver & @WanderLust

Thank you for your detailed responses. 

@Nick Weaver

I was going through graduate architecture programs in Australia and the one offered by NSW interested me a lot. The reason being,

1. Its set in a Tropical climate.

2. Its accredited by numerous Boards.

3. Australia gives 2 years of Student Visa + 2 years of work VISA which I believe will be good enough time to repay the loan and get back to India.

4. Their program offers study with regard to architecture in South Asia and South-East Asia.

Would recommend I aim for this program or other programs in Australia? How are the job prospects for Australian and International students in the country?