I am a citizen and filed i130 for my parents.

I would contact NVC and tell them of the error. They will then return the file to USCIS.

Can I adjust status if my LPR future husband petitions me while I'm in the US with unexpired tourist visa?

File both petitions with supporting evidence and be prepared to prove a good faith marriage.

Son entered US with a different name at age 4. He is 28 yrs old now, does he need to file i-601 waiver with i-485?

Waiver is not filed until after the I-485 is denied. Because he has substantial illegal presence he will face Inadmissibility issues which will...

There is no need to file that information as there is a co-sponsor.

How do i file my I-864 if i dont have a tax return for my most recent tax year?

There is no reason for you to file an affidavit. Your wife and father is all that is necessary.

Is it legal/common for employers to ask a employee to sign a contract while applying for any immigration visa?

Absolutely, not only legal but a good business practice.

Probably best bet is an H1b visa. Requires employer filing and meeting many requirements such as English proficiency as well as State licensing...

Will changing status from F1 to H4 affect TPS and its EAD?

Depending on your needs it may be best to use the TPS EAD and work, and if necessary renew it until the green card kicks in.

Can a H1B petition withdrawn by an employer if employee doesn't join the firm?

There should be no impact on C's approved petition.

I would like assistance with immigration and to marry In The Nassau County Facilities.

Seeking help from an immigration attorney can be done by locating someone through AVVO or the local bar association.