DuckDuckGo has shown their support of anonymous communication before, providing a Tor hidden site address for darknet users. DuckDuckGo should also support I2P by allowing access via its network. The I2P domain duckduckgo.i2p is being reserved by an I2P developer, ZZZ, and can be released to you upon support.
I2P is different than Tor, in that it's not an outproxy. All I2P sites are within I2P. It supports domains, bittorrent, serverless email, decentralized filesystems, and many other technologies Tor doesn't recommend.
An additional bonus would be an I2P address for the xmpp server, and maybe federation with I2P based xmpp servers, but that is more advanced.