I decompiled the "sp_a1_wakeup" level to add some basic geometry and entities.

Since decompiling maps isn't perfect, the voicelines don't play / work for either Wheatley or GLaDOS. Wheatley's animations also do not play, I assume due to the voiceline error.

I'm very new to Hammer and only know how to do very basic level editing and some extremely simple logic. I'm willing to learn if anyone knows how to solve this issue!

This is a result of Valve handling a large amount of the game's dialogue through a VScript which checks for specific map names to know which lines to preload. The script is called scripts/vscripts/choreo/glados.nut, but also handles lines for othe characters. So the proper way to fix this is to edit the script to check for your map's name instead (or spoof the original map's name), and then pack that version into the map.

The other method, which doesn't require VScript knowledge but is more tedious, is to manually place logic_choreographed_scene entities into the map which replicate the original lines. Which approach makes more sense is going to depend on what exactly you're doing, how many of the original lines you need, etc.