Since Squeak is purely Object Oriented I'm fairly certain that you should be able to pass functions as parameters to other functions, but when I was researching on this I couldn't find any information about this. Is my intuition correct? And if so, how is it done and how do I invoke them afterwards?
You're confusing two different things. The only real "functions" you pass around in Smalltalk are blocks, which you pass just by writing a block as an argument (like you do with every ifTrue:). If you want to send a message to an object but have the message be determined dynamically, you can pass the message name as a symbol (e.g. #value) and send it to some object (e.g. with perform:). You don't pass instance methods themselves. Either pass a selector symbol or pass a block that sends a message to call the method.