It’s close, but not quite there yet, as GE link bulbs must be paired with either the Wink hub or the Link hub or the Philips Hue Bridge before Echo can control them.
I use the Hue Bridge and GE links with Echo, works great.
Unfortunately the ST/Hue bridge integration had problems right now. Support says they’re working on improvements.
If you attach GE link bulbs directly to ST, no bridge, you can control them from ST. To add Echo into the mix you have to use one of the various workarounds.
Echo doesn’t have a zigbee antenna, it can’t talk to the bulbs directly. There has to be a wink hub or a philips bridge or something else with a zigbee antenna to act as the middleman.