Connect USB device to a ceiling light
I don't see a non-hokeydokey way to mix mains powered E27 and LED strips in the same fixture, and USB only makes it worse.  Here's what I'd do.  

Convert the whole works to 12V or 24V DC

For the LED strips, you use any of the literally thousands of 12V LED strips readily available for $7 per 5 meters, all over ebay and amazon, or hundreds of 24V LED strips.  

For the E27 screw-in bulb, you use 12-24V LED bulbs intended for RVs.  Most of them work on both 12V and 24V.  

If it has a lamp cord and plugs in, just put a 12v or 24v "wall wart" power supply on the end of the lamp cord.  If you have space up in the lamp,  you could also use a modular power supply such as those made by Meanwell. 

This will not be dimmable.  But for the LED strips, 12/24V dimming and RGB controllers are readily available and could be tucked up inside the lamp.  They use a wireless remote.  This would work for the LED strips not the screw-in.  

If someone screws in a 120V bulb into the socket, it just won't work.