I would start by doing a search for a reputable attorney in your area on Google. Some personal attention from a professional is needed and there...

Unlawful Detainer: Invalidate tenant answer and file default?

Previous attorney is right on. You could try summary judgement but it could be more time money and exhaustion.

Can i have my employee serve the Unlawful detainer to my tenants? or does it have to be a professional server?

Generally as long as they are 18 they can sign a declaration and serve the ud. I also suggest sending a copy by certified mail

Is it any easier to evict a tenant under a 60-day notice than a 3-day notice?

Generally easier with a 60 day notice though a three day notice might be relatively quicker.

Notice of Sale and Entry

It varies by municipality but they generally assume the lease as is. if you are in a rent controlled city they will have to abide by said laws...

Do I have to pay my termination fee if the landlord returns my disposition more than 21 days after I move out?

Not sure what charges you are referring to. Landlord probably revised because he has a duty to mitigate and did so

Can I move w/o penalty from my landlord?

Agree with the other lawyer but be sure to give notice in writing...too often tenants fail to do this which leads to later complications

Don't they have to have a marshal serve a 5 day notice to get out or can they come anytime today and decide to lock us out?

He sheriffs department will have to lock you out

Are we able to get out of our lease early? If so, what responsibilities do we have as tenants?

You can but make sure you have a proper place to move to. Take time to discuss all your options with your family

I have a tenant on section 8. They have not paid their portion of the rent. Do I give a 3 day notice to them and section 8 ?

3 day notices are to give the tenant the opportunity to cure the breach not section 8