It is tough to listen to short clips out of context but my impressions are as follows.
1. American redstart - hardest of the batch for me, redstart is not very distinctive and sounds like bits of other warblers' songs
2. yellow warbler - only likely to be confused with chestnut-sided warbler
3. common grackle
4. yellow warbler
5. common yellowthroat
6. red-eyed vireo
7. song sparrow
A good web site to use for reference is
http://www.natureinstruct.org/dendroica/spec.php/Dendroica+Canada. It's free, but you're paying for it, if you know what I mean, so why not use it.