2 oz of Cascade at 60 in a 3 gallon batch is going to be IPA level bitterness, not APA level.
I'd shift some to late in the boil and aim for 35-40 IBUs total for a .66 BU:GU in a 6.5% APA brew. Figure 1 oz at 5 min and with your software, add enough bittering hops to hit between 35 and 40. Then use the rest at flame out. I would just dry hop it with the mosaic, a hop tea doesn't extract as much aroma as straight up dry hopping does, in my experience, and it always lent a grassy flavor any time I tried it.