I'm creating canvas' of multiple sizes and shapes that have blocks of text that are the same. Is there a way to have edit the text in one instance and have that same text duplicated across all over canvas'?
Set your text once, then drag the text box to the Symbols Panel. You can then place as many instances of the Symbol on different artboards as you want merely copy the original symbol instance (text block). You can even transform (scale, rotate, skew) the symbol instances independently if necessary.
Then if you need to edit the text later, double-click the Symbol in the Symbols Panel. Once you edit the text there, all instances will update.
This is about as close as you are going to get to dynamic copies.