You both can jointly file an application before the marriage registrar for getting married to each other. 

You have to secretly plan for marriage...for that you have to book slot for marriage before registrar with 2 witness once your marriage takes place you will get a certificate in 2-3 days... immediately after certificate you can ask for police protection...

For detailed discussion and more precise course of action you can approach me on telegram....

Or can wite me on Gmail.....

You can approach the Marriage Registrar of your area and submit a written application for your marriage under the Special Marriage Act. You need to follow the prescribed procedure, including having at least two witnesses present for the marriage registration.

1) since both are adults you are at liberty to marry 

2) you don’t need your parents consent for marriage 

3) your girl friend can send letter to local police station that she has married you by her own free will 

4) obtain acknowledgement of receipt of letter 

5) you can get married under provisions of special marriage act 

6) 30 days notice of intended marriage has to be given 

7) you can in alternative get married under Arya samaj 

8) 

Arya Samaj Marriage as such a valid marriage as per Arya Samaj Marriage Validation Act, 1937.

9) written application has to be submitted by both he bride and bridegroom and then marriage date has to be fixed a week later

You both are adults and have decided to marry each other.

You do not have to even obtain the consent or permission of the parents who do not you both to get married for the reasons you stated.

In fact since your own parents are okay with the proposal you can get married to her under the guidance and blessings of your own parents.

If she anticipates her father to involve in any criminal complaint, she can inform the concerned police station by sending a letter by registered post stating that she voluntarily and on her own volition had taken a decision and got married to him, that she is major by age and also employed, hence her  parents eyeing on losing her money are putting an obstacle to the marriage and trying to falsely implicate you both in a criminal complaint.

Since you both are Sikhs, you can get married under the Sikh marriage law itself and not necessary to go for special marriage too.

You take the help of your parents and friends to protect you from any violent assaults or onslaughts  due to this marriage. 

If you both are adults then they can't do anything. Just do a registered marriage that's enough 

If the girl is major and is marrying with her own free will with you, then no one can punish you or any of your family members for the acts committed by the family members of girl's side.

Inter-caste marriages are legally protected under the Special Marriage Act of 1954, which prohibits discrimination or punishment based on such marriages. These marriages also have legal protections for inheritance and property. Therefore, families cannot take legal action against you if someone commits suicide due to the marriage.

Though this is a hypothetical question, the answer is that neither you nor anyone in your family can be held responsible for this silly and mindless act of suicide committed by that person.

You cannot be held for abetment of suicide.

Don't stretch your imagination to this extent.

You can inform the nearest police station that they can react in this way including suicide to save you from false implication of any case in said matter 

Your wife affidavit that she married out of her own free will will save you and your family members 

no case of abetment to suicide is made out against you and your family members 

I'm sorry to hear about the difficulties you and your girlfriend are facing. It's important to understand that marriage without the consent of parents is not illegal in India, but it can lead to social consequences. Here are some steps you can take:

Make sure you and your girlfriend are ready to get married and are aware of the risks involved in going against your families' wishes.

Consult a lawyer to understand the legal aspects of marriage and your rights as a couple.

Plan a small wedding with only close family and friends, if possible, to minimize the risk of any disturbance or retaliation from the girl's family.

Consider getting a court marriage, which is a legally recognized form of marriage in India. You can apply for a court marriage at the office of the sub-registrar of marriages.

After the marriage, make sure you register the marriage under the Special Marriage Act, 1954. This will ensure that your marriage is legally recognized and you have legal rights as a couple.

As for your hypothetical question, suicide is a serious matter, and it's important to seek professional help if someone is contemplating it. If someone commits suicide, it's important to cooperate with the authorities and provide any information you have to help them investigate the matter. If you or your family members are threatened or harassed by anyone, you can file a complaint with the police and seek legal assistance.