PPPoE Web Gui setup

I think that you have to create only one connection, because you really have one connection.
I think that the additional /30 should be configured as a set of aliases of the one and only connection interface: ppp0.

If you would like to make some tests, I'd start removing the eth2, leaving only PPPoE.
After network reconfiguration, when connected to the internet, add the /30 as aliases to the ppp0 interface with commands like:

ip ad ad 76.10.177.152/30 dev ppp0

A ping should confirm everything's working. Also, please show the output of:

ip ad

From this point, we need to find a way to integrate this config into centos network scripts (I just read the manuals, but I couldn't find it).