Connect 2 monitors to 2017 MacBook

Sorry, but no. Your 2017 MacBook (I have one too) can only support "two" simultaneous displays with one being the notebook's display, and the second, being an external monitor. For the external display, your notebook can support monitors with DisplayPort, VGA, or HDMI connections, using the appropriate adapters.

It only supports 1 external monitor.

It will depend on the exact model of your iMac. Only certain models support Target Display Mode. Regardless, this would only allow having the MacBook's screen on both the MacBook and the iMac. I don't believe you can also use a second monitor in this case.

Ref: Use your iMac as a display with Target Display Mode - Apple Support