Question: if static node is purchased and later buyer needs to exit, will the coins be returned or forfeited?
Yes, you get the coins back.
There are 2 wallets for the STaTiC:
1. Contains your coins and you will remove these completely from your computer and store them on paper and stick.
2. Is your STaTiC Wallet and it contains Zero coins...
If and when you want your coins back, you will use you have them in your other wallet.