No need to seal Guava, it doesn't check.
I rather wait a minimum of 8 months before start working on them, ( I was belly tempering a bow yesterday that was sitting for a good 6-7 years and I still had some moisture beads coming out )
I would toast the staves with a heat gun, concentrating on the bark also to kill all possible larvae, I lost plenty staves to worms.
That is not Hearwood, I had plenty staves with those streaks in them, they look great on a finished bow if you don't lose them as you take wood off