Unicorns,

USCIS has estimated that up to 25000 Nepali nationals can get the TPS status. That includes all the Nepali nationals who are in any non immigrant visa status or living illegally here in US land. But, all of them did not apply for the TPS. That could be because of lack of information or confusion about TPS. For example, if somebody with F-1, F-2, H-4 visa get TPS and TPS based EAD and started working, they will be out of status which was 100% wrong. People can maintain both status parallelly.

I have read from some sources that there are all-together 12,000-13000 TPS applicants. However, all of their application has not been approved yet. It's because they have not applied for EAD.

I believe that if DHS re designates TPS for Nepal, the number will be more and the TPS will be more and TPS will be extended for long term. 

In my view, the condition of Nepal and Haiti is similar, economically and the nature of natural disaster. DHS has also re-designated TPS in 2011 for Haiti. Hope, they will do the same thing for Nepal.