Adding a execution delay to a Homey Flow action card seems to be impossible, as there is no action card available with this functionality. It is easy to implement if you know where to look for this functionality as it is a little bit hidden.
Devices within the domotica software Homeseer can be controlled by Homey Pro, for example via Homey Flows. Remote control of Homeseer devices is done by making use of the JSON standard, a standardised text based data interchange format that uses human readable text to store and transmit data. Controlling Homeseer devices with Homey is not complicated.