Everything is relative
Generally, every player is going to be better in LF than in CF and worse at SS than any other IF position because CF and SS are the two hardest positions to play.
If you moved all your players to their best positions all your players would end up in LF and 1B.
Now, for example, your SS might not have any rating at 1B. That's because the positional ratings are based off of the defensive ratings (Range, Arm, Error and Double Play) and Experience. If you play your SS at 1B they will get very good there. Your 1B can also play SS, but will probably be terrible
Certain positions rely more, relatively, on certain ratings. CF and SS - range. 3B and RF - arm.
There's a link in my signature to user studies. One study is about defensive positions. That might be useful to you. Note, though, that the information about LF may not be correct (see my post at the end of the thread)
This article talks about the defensive spectrum
https://blogs.fangraphs.com/position-adjustments/