the sender of paypal can reverse the payment if they do not receive the bitcoin. simple as that.
No if you send as Gift or Friends and Family.You must also send payment as 'Gift' or 'Friends and Family' option. This will prevent a chargeback from you.
By the way, if we can use escrow I want buy.
Or we can use Goods and services, do you want take the risk as you said?

No only Gift or Family and Friends. Yea, PM me if you want my LocalBitcoins escrow link