I currently have 3 sonos 1 speakers and a sonos sound bar. Looking to get an amazon alexa device. I would also like to think ahead about getting an alexa device that I can control other items that might require a hub. My question is I would prefer the new Sonos one with built in Alexa, but would I then need a device or hub to control other items like door locks or lights?
That will depend on the items you want to control not the alexa input device.
For instance if you want to use a wall switch that dims a light fixture you have to have the appropriate hub to do that. If you are controlling the actual bulb directly you can get away without a hub.