I've added three devices (switch, bulb, doorbell) on sinric pro, I have control via Alexa, this works great.
I have a development through Node MCU (esp8266), the switch through relay, the bulb is a bar of LED's 2812 x8 and the doorbell is a pull-up button.
I can't find any information on whether it is possible to share control with another Alexa user, is this possible?