If your i485 and i130 is denied twice, will it be possible to refile again, after two interviews and a stoke?

Yes, you may re-file. However with your previous history it is best to use the services of an attorney at the stage.

Yes he may as long as he makes the requisite income for his household size and number of individuals he is sponsoring.

Do I need to go back to school to maintain my legal status after I marry a US Citizen, already filed I-130 and I-485?

You will have pending AOS status while the case is processing so you do not need to return to school.

Purpose of trip to u.s for older citizen ?

More information is needed to provide guidance. Please rephrase.

Can my partner still get a green card with a criminal record ?

A review of your partner’s criminal record must be made in order to understand any possible consequences.

Do we have to start all over from square 1 with the k1 visa process after denial because of history of drug use?

Yes if there was a denial, then you would need to reapply. The underlying I129F is only valid for a certain period of time.

I filed for 1 130 and called to go for an interview but I have a deportation order will I get arrested when I go for the interv?

Yes that is a possibility so it is best to consult with an attorney prior to interview.

I filed divorced when i751 pending ? Do I lose my green card ?

No you do not lose your green card but you must request that the case be transferred from a jointly based filing to a waiver based one. Recommended...

Can I change employments a few months after filling adjustment of status?

Yes you may change employers with valid employment authorization during your pending AOS petition. You should inform the officer of this at time of...

I wrote pay to the order of "USCIS" on the cheque ? Will they reject the application?

Yes likely as the instructions indicate to address the check to US Department of Homeland Security.