i was an F2 dependent. I applied for Change of Status to F1 and it's approved too. So, this makes me an F1 student now.
I have applied for TPS and its not approved yet. But through TPS, i have got EAD and Social Security Number Card too.

Things has changed. I have changed my mind and want to work with TPS EAD (not in school). I did talk to my DSO and he told me that i'm safe till the last of january 2016 since that is the last date to report in school. I don't want to go college now. In this situation, while on F1, Is it okay to start to work outside (morethan 20hrs) before january 31st with TPS status pending on "Finger print fee was received"?

But i'm planning to join university (same university but different subject) for the Fall 16 under TPS status. अहिलेको F1 छोडेर पछि TPS सकेपछी फेरी नया थालेको subject मा F1 मा auna केहि समस्या पर्ला कि के होला भनेर/
Thanks in advance.

Your post is hella confusing.

From what I understood here's my suggestion.

F1 and F2 are statuses , TPS is not.
You can have (TPS and F1) or (TPS and F2) or (illegal and TPS), so there is that.

While you are on F1 you can still work on EAD via your TPS. No need to mention to your DSO (not his domain of interest).
While on F1 you can also qualify for reduced course load so you can take only one class per sem if that helps.

Regarding the last paragraph --
Again , F1 is a status and TPS is not. If you give up your F1 you will be and illegal immigrant with a TPS status (which just means they cannot deport you for being illegal.)

I have heard mixed reactions from DSO's regarding changing status from TPS to F1.
It is absolutely possible to reinstate an out of status F1 with TPS back to F1 but that's a whole another Mahabharata right there.

Thank you for your words @fdpower
Okay, now i think i have two options to remain in status.
1. Register for classes and maintain f1 status
2. going back to f2
3. Staying in TPS and illegal status

Firstly, i cannot register for reduced course since my TPS status is not approved yet(am i correct?), though i have EAD and Social Security Number through TPS. i don't think it will get approved by the end of January. Secondly, I do not want to register for full courses (huge money) since i'm planning to apply for next Fall. I have been talking to Program director for graduate study and it is almost sure that i will get graduate assistant ship for another program.

I'm thinking about to abandon present F1 status (was planning to study paying tuition fee before TPS things) now and stay in TPS only for 6/7 months. Is it possible to come back in F1 status again after 6/7 months (for different program/new i-20) from TPS status only?

If not, i'm ready to go back to F2. For this, I think i should leave US (correct me if i'm wrong) before my f1 get expired (i have 15 days only for that). What happens to my TPS status if i leave US now and come back in another F2 VISA? (ahh! alot confusion)

Please, suggest me what is the best thing to do in this situation.

Firstly, i cannot register for reduced course since my TPS status is not approved yet(am i correct?)
-- > No , you can.
https://www.federalregister.gov/articles/2015/11/09/2015-28360/employment-authorization-for-nepali-f-1-students-experiencing-severe-economic-hardship-as-a-direct

https://www.gpo.gov/fdsys/pkg/FR-2015-11-09/html/2015-28360.htm

"DHS is taking action to provide relief to the Nepali F-1 students
experiencing severe economic hardship as a direct result of the
earthquake in Nepal in April 2015. These students may request
employment authorization, work an increased number of hours while
school is in session, and reduce their course load while continuing to
maintain their F-1 status."

Is it possible to come back in F1 status again after 6/7 months (for different program/new i-20) from TPS status only?

--> possible yes but decision is soley upon DOS's discrection for reinstaement so check with DSO.

My suggestion ,
Maintain F1 or F2 notmatter what.
With TPS and F2 you can take classes on a cheap community college and then move to F1 and transfer the courses.

@fdpower
This is what i have found here....
I was lawfully present in the United States on April 25, 2015 but in F2 non-immigrant status.. My change of status from F2 to F1 was apporved during the last of october..
अब नेपाल गएर F2 VISA लगाएर आयो भने ऐलेको TPS पनि जान्छा हो ?

This notice applies exclusively to F-1 nonimmigrant students who
meet all of the following conditions:
(1) Are a citizen of Nepal;
(2) Was lawfully present in the United States in F-1 nonimmigrant
status on April 25, 2015, under section 101(a)(15)(F)(i) of the
Immigration and Nationality Act (INA), 8 U.S.C. 1101(a)(15)(F)(i);
(3) Are enrolled in a school that is Student and Exchange Visitor
Program (SEVP)-certified for enrollment for F-1 students;
(4) Are currently maintaining F-1 status; and
(5) Are experiencing severe economic hardship as a direct result of
the damage caused by the earthquake of April 25, 2015.
This notice applies to undergraduate and graduate students, private
kindergarten through grade 12 (K-12) students, and public and private
high school students. An F-1 student covered by this notice who
transfers to another school that is SEVP-certified for enrollment of F-
1 students remains eligible for the relief provided by means of this
notice.