They never gave me an exact date.

All your first set of questions can be answered by looking online or calling several local competitors.Your accounting questions though, show such a lack of basic knowledge that you probably shouldn't be doing this until you have more experience.

I keep reading different things online.

1) You would just write an addendum stating that the lease is extended to whatever date and everything else remains the same.

And up-to-date.

Leases where due to me on 10/17, but on that date I had only received one.

Currently I use an app called "meet up" and for some time, a lot of their events in my area are all done online.

One applicant mentioned their desired move-in date in 9 months in the future but that move-in date is way too far from our earliest move-in date (2 months from now). 

Look at a few each day online, or catch up with an agent who knows their stuff and househacked to give you some pointers. 

Marketing homes during this period involves creative strategies, such as seasonal staging and targeted online promotions, to attract buyers even amid holiday distractions.