they can  be attesting witnesses 

2) problem would be if they refuse to cooperate in filing affidavit in testamentary petition for probate of will 

3) they may refuse to attend court to give evidence in support of testamentary petition 

They can attest the will if they are not beneficiary to the same directly or indirectly

Yes they can be witness . There is no problem it is legally valid.

Yes. Any person who is above 18 years of age and of sound mind can be a witness to the will.

Pros are that you will actually be present to see whether any misappropriation of the properties of the testator is not done and the said will is not executed under any sort of coercion, undue influence, fraud and miss representation.

Cons are that you might be called to be a witness if any dispute arises letter on with respect to the said will.

of course they can be attest. anyone else you know who isn't a beneficiary can be a witness, such as a friend, neighbour or colleague. 

no harm in the couple attesting the Will as witnesses

Any person above 18 years of age and with sound mind can be witness. Only precaution require, he/she should be trustworthy.

Dear Sir / Madam 

To become a witness of will doesn't have any negative besides the fact that you have to identify during probate or when legally challenged.

Hello,

There is no cos neither there is any pros. If you at all consider it a con then in case there is a dispute regarding the will in future then you might be summoned in the court to depose .

Regards

Any person who is not a beneficiary to the bequest made in the Will can be an attesting witness to the Will, there is no legal infirmity in it.

Yes any one who is major and have sound mind can attest the will as witness even if they are not beneficiary of the will.