theinkinjapan

I think this is the best plan.

You got 80% of your money back which is good.
.....so this lesson only cost you a few bucks !?  You got off lightly 😅

It’s a no brainer, you don’t get involved with gangsters. Especially if you got a 2 year old.  

Checked out this Youtube channel. The chap on there makes short videos on precious metals. On some videos, how to spot and test for fakes.
https://m.youtube.com/user/CyberCurtainTwitcher/videos

I wouldn't say the guy was running a scam. He was just selling garbage with a high asking price, you agreed to pay it without doing your research. And I'm not being glib or anything, because I have done exactly what you just did myself, and bought some cupronickel commemorative Churchill crowns for £3 each when they are worth pennies.  
The key thing here is that you haven't lost a large sum of money. And you won't do it again. Relax, and maybe look at buying something else from a reputable seller to take your mind off it. 

I know what you mean about too good to be true. Maybe I have seen Antiques Roadsow and Pawnstars one too many times. He wanted about $18 for the Morgan, which didn't seem far from what a quick search told me market value was. I definitely thought there was a good chance that at least 1 of the coins was fake. I especially doubted the Russia one being real because although I had no idea what it was at the time, I expected something that old to be more valuable. 
I guess like many people,  I was hoping I had found a bargain, and was counting on the seller being unwilling to do his research, but that is probably much rarer than the buyer being ripped off.

I paid 5000jpy, approximately $45USD, for these 3 coins at a street market in Tokyo that they hold a couple of times a month. I don't really know what they are, so my questions are so my main questions are:
Are they real, what are they, what are they roughly worth. Of course, my main initial concern is of course are they real. I would normally not risk buying in a market but I figure the chance of being ripped off is less in Japan. 
The middle one, I am guessing, is a trade dollar? After getting it home, I did note that some parts, especially the edge have green tarnish/corrosion. I also see black on the rim, so there are black, green, and silver, but I don't see any other colors, like copper. I can take more photos and weigh coins if helpful.
The American silver dollar looks fine to me based on the modern silver dollars I own that I bought from reputable retailers, but I don't really know. I looked up the O and it said that means it was minted in New Orleans. That is all I know.
The last coin, I guess is Russian (or fake Russian?) After getting it home I note that it looks oddly black, and the black did rub off with my thumb, is this artificial aging or ligit? Another suspicious feature is that the lower part of the coin seems to have been worn off, or been cut off, but as there is clear Russian printing around the rim, it surely hasn't been worn down or cut. Maybe it wasn't centered correctly, but that would happen when coins were struct, not cast, and I would guess they were casting at that time?
Magnet wasn't attracted to any of them. I didn't try magnet on a string to test for slight attraction. I think I read that somewhere. If a magnet isn't attracted is the most likely material copper when it isn't silver? 
Any tips for the future? I am wondering if I should get a guarantee from the seller in the future. Like, if it is proven not to be silver I can return it. In this particular market, the sellers are regulars and I think they may get their stuff from estate sales.
https://photos.app.goo.gl/Vy9hVKhUsYdNYwct7

I've downloaded the pics and added them directly to your post.  It is better to attach pics rather than have them linked elsewhere so viewers don't have to click off and open extra pages.