How small are the faces you are trying to import? SketchUp is a great program but it can struggle a bit if things get extremely small. Specifically, SketchUp will ignore faces with a area smaller than 0.001 inches. Next, can you post the model itself so we can take a look and make sure that there is nothing wrong with it on a more technical level? If you can not post the model, some screenshots would be the next best option.
As for your second question, if I recall correctly, there is a way to import things and place them via a coordinate system. I will see if I can find a write up on how to do it, and if I can’t find one, I will write something up for you as soon as I have a chance.
I looked through some materials and I can not find a way to directly import to coordinates but you can use the move tool to move items to a set of global coordinates by using the square brackets. For example, typing [0,0,0] will move selected items to the global origin point. For more tips on using the move tool, try this link: https://help.sketchup.com/en/article/3000090.
I realize that this is not an ideal solution and I will keep looking to see if I missed something, or if I can find an extension for you.