I can help you out mostly with the first one.
To import a tileset, make sure you have it saved to your computer. Then, open the MaterialBase (Tools>MaterialBase or f10). Click in the materialbase "Tilesets" so it's highlighted. Click on import, and find the tileset on your computer. Left Click on the color you want to be transparent (completely gone[usually the background color]), and Right Click to set the Semi-Transparent Color (partially gone[shadows]). Then, you have to go into the database (tools>database or F9) and click on tileset at the top (third from the right). Increase the array size, then set the tileset graphic as the tileset you just imported
Passage is whether or not the character can walk on the tile. Circle means the tile is passable, X means it is not. On auto-tiles, a square means the player can pass it as long is is one tile thick. You can pass if the tile is widthwise (----), but not heightwise ( | )
4-way Passage is a more in-depth form of passage. With this, you can say if the character is standing on the tile, he can only move in certain directions. However, if one tile says you can move <- ->, but the tile on the right is only ->, then you can't move from the first tile to the second one.
Priority is the "level" the tile is on. If the tile has a priority of 5, then it's on top of everything (unless a tile on a higher level also has that priority). This is used on things that should go above the player (roof auto-tiles, bedsheets, the top of two tile plants, etc). The higher the priority, the higher the "level" the tile is on.
Counter means that you can interact over it. If there's a NPC you can talk to, but is behind a bar, if the barpiece has the counter flag set, then you can talk to the NPC over the bar.
Terrain tags are basically useless. I've used it to set areas before (have the area have a certain terrain tag number, set variable to player's terrain tag, if terrain tag = X, then enable encounters, if not, then disable encounters. That's about the only use I can think of for terrain tags. Anything with a terrain tag that's not 0 has priority on the top layer.
I'm shit with animations, so I can't help you there.
My mapping is shittier than my animations, so I definitely can't help you there.