I am newly married and will be sponsoring my wife and her 17 year old daughter using the 1-864 form.

An agreement not to receive support does not relieve the sponsor of the requirements of the affidavit of support.

How long does it take for USCIS to respond to the fraud tips given by email?

Depends on their priorities and resource availability. They will not provide you nay information as to there action or inaction on the information...

Can I find out if someone has filed for a green card?

Only if they provide you with the information

My mom on visitor visa from India and she has shopliftingCase and if her case dismissed, can she return back Usa after some time

A dismissal particularly if it comes based on a diversion program may be at times considered a conviction for immigration purposes. Your mother...

if you are having trouble completing the electronic version correctly, file a paper version. Better to file correctly.

I have sponsored my sister to immigrate to the US. She is a Canadian with a home in Florida. Can she come and go as she pleases?

Your sister must maintain her non immigrant status, which includes intent for admission to the US.

I filed Form I-751 and I did not receive the receipt yet. is that normal ?

Yes it is normal at this time as USCIS is having issues sending out receipt notices

Not an immigration question moving to criminal

Can h4 travel from India to USA with 15 days prior to visa expiry

The visa needs to be valid at time of admission and you must have a valid passport.

How to remove waiver?

If you have the two year requirement you may fulfill it by returning to your hove country or have it waived. There are various waivers available...