Somewhat. This problem shows up in the OS as well. The fix you posted is adding video drivers while in PE.
I had originally tried that for when the summary screen shows an error in WinPE but the additional drivers didn't make a difference with an HP Elite x2 and a Surface Pro 4. WPEInit still ignored the custom resolution on both models.
I found the setting for the summary screen under this file: \Scripts\Summary_Definition_ENU.xml The problem is partially these two lines:
<CustomStatement><![CDATA[ window.resizeTo 700,500 ]]> </CustomStatement>
<CustomStatement><![CDATA[ window.moveTo Window.screen.width/2 - 700/2, Window.screen.height/2 - 500/2 ]]> </CustomStatement>
Adding code to replace those two lines during deployment to get the properly scaled value (if DPI Ratio = 2, then the first line should be 1400,1000, etc) make it appear much better, however the "Finish" button is still getting cut off. I'm having trouble understanding what file is causing that. The Wizard.css seems to set the fonts and colors, but I can't yet tell how the button margins are being set.