Hi Michelle,
Just keep your eyes open for new pieces - I actually find that most of the kids are really happy playing the lesson books since every piece to them is making music on the piano. However, there are some old fashioned favourites written out - by the way, I have found I like them but they are meaningless to the kids since they didn't learn "lightly row' 30 years ago! LOL!
Anyway, the lesson series are usually pretty good at giving a sound basis for several levels. I am not as familiar with Alfred, but I know level 1 is still quite enough in itself. They are just learning to read still. I use the Faber Adventure series, and fidn there is a gap in progress once you get to level 4. I introduce more classical repertoire towards the end of 3B.
However, I try to respond to the inclinations of my students. If they are playing around trying to work out a tune, I try to help them - but I try to encourage them to figure as much out first as possible so they develop aural skills.
I do recommend Dozen a Day, though. You can approach this one hand at a time form level 1 and careful teaching of technique makes this book very valuable imo. Some studetns get rather excited that the reading is simple, and rush ahead without following the precise movement insrtuctions, but at least they feel good about playing something 'easy'. In other cases, I have found it to be the best thing since sliced bread! We focus on reading and playing music from the lesson books, and technique from the DD.
As for scales, if yo uare using the lesson books they introduce things like passing thumbs under for scales in time. Unless you ahve a fast student who is itching to try new things, the books give a context for a skill that is not as easy as it seems. Passing the thumb under too early can throw off the hand position for some and it really is not necessary to understand more than 5 finger scale patterns in the beginning.
About metaphors, what I do is go with the inspiration fo the moment. I don't have a repertoire of metaphors - each student is so different that what makes sense to one is pointless to another. I just try to be creative. Like, the other day I was showing a little girl (6) how to play the chromatic scale. Her hand was getting a bit flat, so it seemed to me that she should have a little crab crawling up the keys on its tip-toes. It didn't want to eat sand for dinner!
Good luck
Topic: Essential Repertoire for a Beginner Student