These are native-comp warnings. They are not uncommon when
native-compiling Org (not only org-fold.el) and generally harmless.
If you are sufficiently annoyed with them, most of these warnings can be
"fixed" by declaring the missing functions. The functions are available
at runtime, but not during native-compilation.
I am not sure I understand fully, but are you suggesting that the problem is because I forgot to compile org and therefore these files were being compiled during runtime? Would running "make" solve it then? I have done that anyway since I was not sure if I did it earlier.