Is there any way to do voice control through an Alexa without the cloud (i.e. without a myopenhab account)?
Yes, you can create your own openhab cloud:
Just an explanation. You need some sort of cloud access because Alexa is strictly cloud-based.
Hue emulation works with alexa.
Yes, I do it without myopenhab cloud. But this requires (1) deploying the alexa skill yourself (2) deploying the AWS lambda code yourself.
Regarding (1) you can deploy the skill as a development skill, which means you don’t have to how through the entire approval process.
Apparently, it’s possible to use a set of Node-RED nodes to expose items to Alexa via your LAN.
I haven’t tried it (because I don’t have an Alexa) but one of my installers found it and says it works well.
It might be this set (I’ll ask for confirmation)