If the 10 XRP minimum is not met, any amount under 10 XRP that is sent to the new wallet will not go through and be returned to the sender. However, once the 10 XRP minimum is met, you can then receive any amount of XRP into your wallet.
This minimum balance amount is not something that Edge chooses to do but is part of the rules set in place with the XRP network that applies to all other wallets as well.
XRP requires that it applies reserve requirements. The reason for this is to protect the network from spam transactions or malicious usage (https://developers.ripple.com/reserves.html).
Once the 10 XRP balance is met, the funds will also be locked and you will not be able to spend or go below that amount.