HDMI dongle shouldn't break the bank. Sounds like you've already lost considerable time tinkering around.
1080p version - $39
4k version - $63
http://www.fit-pc.com.au/#!appliances/c17lp
or
$35 for the 1080p version from a reseller in Victoria.
http://www.yawarra.com.au/shop/acces.../fit-headless/