Our salary if we amnesty/trade Pierce and KG retires is 46.2M according to hoopshype.
I still don't believe this is necessarily correct.
Garnett's salary for next year is guaranteed at $12.45 million, and another year after that for at least $6 million. There would need to be some sort of buyout, although that could be stretched (over as many as 5 years, I believe).
I know KG is a team guy, but assuming he won't take a single dollar contractually owed to him upon retirement seems like a huge assumption.