The delay is there to allow openHAB to start and the extra UI HABPanel to load. The new UI we use is lighter and this will be shorter. Till then you can try loading the default UI from a web browser but this will involve hitting F5 (refresh!) all the time on your computer which may “add” more to the delay 
That should be enough I suppose. Did you use the right “numbering”. There are various numberings for the Pi (about 3 I believe). Check the numbers we already use to understand which one we use and adjust it.
Can’t see why not as long as the signal on the other side is strong enough and clean to trigger the relays.
Schedule is not yet supported (by openHAB) yet. Cooling is available in the HVAC model and the HVAC version of the openHAB files. See the files with hvac in their name in here:
or type:
ls -la /home/pi/scripts/*.hvac.*
You can enable or disable HVAC with these scripts on the same folder.
HVACDisable.sh
HVACEnable.sh
Thanks 