Mere hiding of some facts from your spouse, cannot be a ground for the annulment or divorce.
1. I have proofs that she has two sets of parents. Does it make good 420 case?
Do you have proof that indicates that you were unaware of the fact at the time of marriage.
Mere proving two sets of parents will not work.
2. Post 498a, I got threatening calls/text message from her side person and this incident occured in USA around 4 years ago. Can I combine 506 along with above case ?
What do you mean by “her side person”? Did she call/has sent any messages regarding this with her own mobile (where SIM is registered under her name)?
The incident is 4 years old.
Section 468(2) of The Code of Criminal Procedure enumerates the limitation period for offences as according to the term of imprisonment for the offences.
“The period of limitation shall be - three years, if the offence is punishable with imprisonment for a term exceeding one year but not exceeding three years”
Punishment for criminal intimidation 506 IPC —Shall be punished with imprisonment of either descripttttion for a term which may extend to two years, or with fine, or with both.
So, since the incident is 4 years old, so, this falls under the bar to take cognizance after lapse of the period of limitation
The evidences (call record/messages) that you have, can be used from the defence side during the trial of 498A.
3. Can I file divorce based on cheating ground?
No. It depends on the impact/weight of cheating.
Let’s say, Spouse has an extra-marital affair and has physically involved with someone. He/She has concealed these facts with his/her spouse and cheated her/his husband/wife. So, here cheating is a good reason for divorce.
But if, the spouse goes only to meet her/his past bf/gf in any public place and concealed these facts with his/her husband/wife. Then here the cheating cannot be a strong ground of divorce.
You can file divorce u/s 13 HMA, with proper reasons.
I would rather suggest not to file it now. It is not the right time to file it. 498A will proceed even after the divorce. So, why you want her to enjoy the freedom after the divorce while you still need to fight against 498A. Have her also taste the proceeding of the courtyards.
First, get acquit from the changes (498A and other (if any)). Then, you can file the divorce. And that time, you can show cruelty as a ground while filling the petition for divorce.