Latitude 5480 has an Alps I2C touchpad, not the same, won't work.
The E5550 should have an Alps PS2 touchpad, try SkyrilHD's version, although it should have been integrated into Acidanthera's.
https://github.com/SkyrilHD/VoodooPS2-ALPS
You shouldn't have to add any kext to /L/E or /S/L/E
AppleALC.kext will have HDMI audio support too, you just need to patch the framebuffer for HDMI audio