Expats that have successfully opened restaurants/cafe in Nepal

Kimone, those are very good questions you ask. Let me try to start to address your concerns the best way I know how, one by one, and let me start with:
RECOMMENDATIONS
1. First, I would strongly recommend that you go to Nepal and spend several weeks there, to familiarize yourself with the country, its people, the current situation, business environment, etc.
While there, I would definitely go and personally meet with Department of Industry  (DOI) officials and get as clear an idea and understanding as possible of Government regulations and present requirements in respect of making an investment in that particular sector of industry (i.e. restaurant/cafe - leisure industry) - Note:  Try and secure an appointment with the Director General of DOI himself. Seize that opportunity to ask about present minimum capital requirements, specifically amount of capital they will expect you to bring into the country through official bank to bank channels? And as DOI works closely with Immigration, ask about the prospects of obtaining a Business Visa AND how long the first one will be for, and the ensuing one etc. My guess is that the first business visa they will be willing to give you (initially) will not exceed six months.
Footnote:  They used to grant Business Visas of up to 5 years, but in recent times, one is more likely to get no more than one year business visa, and then ONLY if you meet their criteria of a, b, and c. which they have now set up. They are now stricter - less lenient - than they used to be, in past years.
Also, keep in mind that the prospects of being able to borrow for your business in local Nrs currency are virtually nil. They expect dollar inflows or other foreign currency from foreign investors.
2. While there, therefore, also be sure to go and meet with the Manager or Deputy Manager of one of the leading banks in Nepal, based in the capital of Kathmandu, and get his input. Take that opportunity to ask him about repatriation or "financial exit" of your capital, earnings etc and how well the regulations that may be on the books are applied?  Will they let you take your money home at a later time is the real question? See what he tells you?
3. Talk to a well established lawyer, but not any lawyer, and not a Notary Public. If possible, take the time to verify his information with that of a second lawyer, is my best advice...and compare notes!
4.  Being able to understand nepalese language is a definite advantage. This is not easy, but if you plan to enter into business there, at some point down the line, I would definitely take lessons in nepali.
GUIDANCE
Keep in mind that doing business in Asia is not like doing business in your country.
There is nothing simple about doing business in Nepal. There is lots of bureaucracy and pitfalls associated with it. Do not believe everything that is said to you, obviously! As for the written contract, it is only as good as the person who signs it. There is a "Contract Law 2058" - as I remember - on the books, but in Nepal, the nepalese people themselves, who are honest, will readily admit that laws on the books can often be interpreted in "75 different ways" and those are their own words!
This is one of the many reasons as to why Leases are not as good, say for running a restaurant or cafe, as Ownership.  Being a lessee and being proprietor are two vastly different things.
But then, it is all about having or not having the required financial resources, for any given project.
EXPERIENCES
I have been away from Nepal for quite some time now, but I think you will find that if you talk to people, they will tell you that the number of failures in the field you want to go into probably vastly outnumber the number of successes. But this is not to say that it cannot be done because two foreigners in the capital have succeeded in doing just that.  Everyone in Kathmandu knows who they are. One runs a very good french restaurant, and the other operates a wonderful italian pizzeria-restaurant, and both have been highly successful over the very long term, and both are to be commended.  If you are able to meet them, they may be able to share with you information relating to any problems they may have had in the field of labor/worker relations and that sort of thing?
Doing something outside of Kathmandu is another possibility of course, but then other contributors who know the countryside better than I are no doubt much better placed to give you proper advice, guidance ......and who knows, possibly make different recommendations to you?
Just one final word of caution:  try to be your own boss and have 100% control.  No local partner or partners is my best personal advice. I think you will find that this is the case for the two examples, previously alluded to.  I was not so lucky with my venture in Nepal and I am not the only one, nor the last one!
Let's be honest, there is nothing simple about trying to do business in Nepal as a foreigner - to this day it's dicey - and carries with it a definite element of risk. Don't take anything for granted.
Be interesting to hear from other contributors, and to read what THEY have to say on the subject?
This is just one person's opinion.