FINALLY just got the ending myself, and I wish I had anything useful to add, but I don't...
I wanted to share the 15 minutes leading up to it, but the share function on PS4 seems very picky about how far back it goes in terms of video, so I ended up only catching the exact moment of the third giggle and the ensuing phone call, which is probably of no help to anyone.
Basically what I did was this:
1. Do the 10 step thing. (I've noticed that you can get the first giggle with this no matter where you start from. As long as you wait until the chimes are over. In my case, I was walking from the radio to the telephone, but I'm pretty sure it doesn't matter).
Interesting tidbit: when the chimes started ringing at 00:00 the ghostly muttering did NOT play for some reason. I thought these sounds went hand in hand, but it was ONLY the chimes this time. Lisa didn't start moaning until the chimes had finished and I had already started walking. This did not prevent the first giggle.
2. My intention on this try was to just let the game idle and do something else until the controller started vibrating. After all, once you get the second giggle, you're pretty much set. The only things I did were this:
- Walked around the hall and looked at the pictures a bit.
- I then placed myself in front of the telephone, started at it (with R3) for a while and let the game idle.
- After 20 minutes or so, I thought I noticed the controller rumbling so I switched back to the game (I was actually playing on Wii U in the meanwhile, lol), but nothing was happening.
- At this point, I decided to walk to the bathroom and stare at the fetus. Lisa was roaming around and appeared behind me in the bathroom mirror.
- I put down the controller again and let the game idle until, 10 minutes or so later, it started rumbling. I switched to the game and lo and behold, the baby was giggling and the phone started ringing. Unfortunately, because of the above PS4 sharing problem, I do not know when or how the second giggle occurred,
- I WAS NOT SHARING/STREAMING ANYTHING
- I DID HAVE THE SHABBY PS4 MIC ATTACHED, but it did not seem to respond to anything, so I highly doubt that it has anything to do with it.
- I WAS PLAYING THE WONDERFUL 101 AT THE SAME TIME AND I'M PRETTY SURE THIS IS ABSOLUTELY NECESSARY