The content of your study plan seems fine. To be perfectly honest, i think you would be ok with little knowledge at all of the language if you plan on staying for 2-3 weeks. Obviously every little helps though!

I just say this as when me and my friends stayed we had little knowledge of the language (me being the most knowledgable) but we got around quite alright without having to use it. But the stuff you plan on using will be fine and will help in some way.

I think learning numbers and common phrases will be the most important, for reading trying to identify some foods on menu's would be helpful (i.e establishing a vocabulary of food). Sometimes we had order food that we didn't know what we were going to get