Picked up an old bug infested mower from a local hoarder - think we can get it running?

By we I mean the collective might of this forum.  I could dump it but I figured why not have a new project to start to see if we can get it all going again for the fun of it.
 
Here's the video tour (just pretend your name is Cody):
 
https://drive.google.com/file/d/1VOHbWoPnpFnA74MS94vAR_hSamjdf0EX/view?usp=sharing
 
Also it's upside down for some reason, so thats cool. 
 
I took a closer look at the pull start, the thing really does not want to move much:
 
https://imgur.com/u8CzbMQ  (it has audio)
 
I took off the air filter cover, there was no air filter, so I am going to need a new one of those. Also, I think it has an ant infestation, so I am going to need to hit it with a flamethrower to get rid of those.
 
So, besides putting it out on the curb for someone else to take this trash off my hands, where should we start to see if we can bring it back to life?  Right now I see the pull cord and the tension wire for the engine cut off being some major issues.  The pull cord can hardly move right now as you can see on the second video.  
 
Time to learn!  If we can get it fixed and I can sell it for more than I spent in parts I'll buy everyone a diet beverage (no ice) next time you are in town.

Oil: Not sludge yet, its black but it still has some viscosity left in it.  Obviously needs to be changed.  
 
Fuel tank is bone dry.
 
Engine, took some pcitures if these help. having a rough time reading the numbers but the first set looks like "160602"?
 

 

 

 
Went under and took off the blade:
 

 

 

 
Its straight and it spins, not easily, but spins, and the engine bits up above (I should learn the terms) also spin so the connection is secure from the engine down to the shaft.

That machine has been sadly neglected. For one thing the motor will not turn over easily because the blade is missing, it is part of the flywheel system. Remove the cylinder head and check the walls for scoring or galling, if that is present the engine is junk. The first characters are 12 which indicate the engine displacement. The next one is a letter or number.

I personally would take some fine sandpaper to those numbers to make reading them easier. 
Then maybe head over to:
https://www.briggsandstratton.com/na/en_us/support/manuals.html?icid=homepageredesign_manuals_icon#
 
And see if you can find manuals for the engine.
 
But yes on a rotary push mower the blade is important for the flywheel effect it gives. 
 
Maybe the next thing I would be checking is does it have good spark, if you mentioned this I missed it.
 
Then I would want to know if it has compression. A leak down test would be great but just a good feel while spinning over with starter cable should tell you that much.
 
If all that checks out I would be considering cleaning the carb. But that takes a bit of careful work and a good place to work especially if it's your first time doing it! 
 
As a side note to this I could never understand how someone could let a mower get so bad from neglect. But then I could say I'm glad there are people like that, see I have only bought one in the last 50+ years. That one was abused mowing what was a cornfield to be our lawn. Bent the crank but did still run when I gave it away. Since then I have given a few away and even sold one and right now I have two that are good to go with one or two tuggs on the rope! 

Run a quick compression test by tying the bail down then with the spark plug disconnected flip the blade backwards. If the compression is good the blade should bounce back.

New video!
 
I got the bolt off the carb after a two hour liquid wrench bath.  Sprayed about a can of carb cleaner on and in and through everything, put it all back on.  I did something wrong with the choke lever as its not working and I cannot at all right now figure out how I attached it wrong.  I put it back on how I thought it looked in the picture when I took it all off.
 
Here's the dirty before picture showing how its hooked in on the right most hole on the carb:
 

 
And here is the video of it cleaned up and reattached.  The lever isn't moving the value, its only staying open.
 
  https://www.youtube.com/watch?v=8MZB9pdYMtA

 
Thoughts?

That is not the choke but is the throttle vane.The governor spring should be pulling it to wide open when the engine not running.
 
You got a primer setup. Note that the air cleaner base do tend to warp requiring a modified gasket setup to get the primer to work.
 
EDITed for missing wording.

IT RUNS!  I GOT IT TO START!!!
 
I have the carb cleaned, the gas tank patched, and more. It now starts after a few pulls and the blade spins and everything works as it should for cutting grass. All except the muffler which blows non stop white smoke out and gasses out the entire street.
 
Photo: https://imgur.com/a/Mr3nybc
Video: https://www.youtube.com/watch?v=6mvGke8UgR4
 
When I first was dumping the oil I didn't realize there was an oil plug on the bottom so I tilted it on it's left side, almost upside down, to get everything out from what was sitting in there for its years of no use.
 
I have let it run for a while and nothing is changing. The oil in the reservoir isn't going down so it doesn't seem to be burning up what's still in there. I cleaned up the mess you see in the video after my first run, I think that was all the carb cleaner shooting out, since then only gas is coming out, no liquid.
 
I could cut my lawn using a gas mask, but I would prefer to try to just stop the smoke instead.