The overlap problem is because the maps aren't actually overlaid. I can see in the Object Manager there that there are two separate map objects. This means that the base map (the BLN file) and the map with the contour/post layers are completely separate from each other and not spatially related at all. The fact that they're sort of in the right place is just because Surfer creates the maps in the center of the screen by default. To snap the maps together according to their coordinates, select both maps (CTRL+A) and click Map | Overlay Maps. That will combine the maps so you have all three layers in one map frame. In the future, you can also create the contour map (Map | New | Contour Map), and then add the post and base layers to it (Map | Add | Post Layer, and Map | Add | Base Layer). That will also create the three layers in one map.
The second issue with the blanking I believe is resolved, since I received an email from you with a different question about the blanked result (so blanking was successful). Let me know if there is still any problem.