
No, it isn't. Form I-130 confirms a family relationship and fixes a priority date. The green card comes later, from an immigrant visa application at a consulate or a Form I-485, and only once a visa number is available.
Yes, and online filing reduces the fee by US$50 under 8 CFR 106.1(g). It is not open in every petitioner situation, so confirm your case qualifies on the USCIS form page before relying on the lower figure.
No, it does not. 8 CFR 106.3 lists the forms for which you may request a fee waiver, and Form I-130 is on neither the unconditional nor the conditional list.
No, it cannot. Premium processing is not available because it is designated only for specific nonimmigrant and employment-based classifications, and family petitions are not among them.
There's no numerical limit. A citizen may file separately for a spouse, each child, each parent, and each sibling, and each petition carries its own fee and priority date.
An approved petition generally stays valid as long as the relationship continues, and can be revoked if the relationship ends or fraud is found. Confirm the position with an attorney before relying on an old approval.