Are wedding videos important for H4 interview?

No, wedding videos are not important. The US consulate does not allow electronic devices inside the building.

How can naturalized US Citizen apply out of status father's green card?

It is possible to file the I-130 for father in this situation. Highly recommended that you work with attorney given the complication though

Hello

The safe route is for them to wait until you have a valid I-797 approval they can present

ON what base can a visa transfer be denied?

Each case is adjudicated on its own merits. If the transfer petition does not meet the eligibility criteria, it may be denied accordingly

While my Fiance's K-1 visa is processing is it ok if she comes into the USA under a tourist visa?

It is not prohibited but it can be difficult to prove that she does not have immigrant intent

Marriage based green-card applied. H1b 7th year extension possible?

No, you cannot apply to extend beyond the six-year Max in this situation

Applying for greencard after marriage ?

This question has been asked and answered

Unrestricted would mean that there are no conditions on who you can work for or where you can work. As you know, H-1s are Employer specific, so...

I got approval Visa tourism to usa and after month i applied for my kids to get the visa as well but they didn't get it so why ?

Difficult to say, would need to know more about the facts of your kids cases.

Can I Join the start up which e-verification is pending?

Yes a new co can enroll in e-verify and sponsor a STEM OPT EAD extension