Hmmm . . . tough questions, Christine! Hopefully, you'll get more answers than just me, but I'll definitely try to help!
So, naps have always been harder for my DD than bedtime. But, I think since Sophie has had success, that means the timing still might be off. It's hard to know on the morning you gave us, since she was in and out of sleep a bit. What was the last successful A time you had? I'd try to stick with that as much as possible. Or, what I've done in the past is really watch my LO for a few days in a row at the time I think she might be ready and then I can usually get a pretty good feel for it. But, sometimes their cues can be pretty hard to read at this age. This doesn't sound like much help at all, sorry!
I do think she's OT though, as she seems to be having a hard time with most A times you try. What I've done in the past to get out of OT is drive my LO around for naps for a few days. It means I have to give up some of my plans for the day, but when she's really stuck in it, it's been one of the only things that has helped. So, I would drive her for an hour in the morning around 9:30 am and then again in the afternoon around 2:00 pm. Now, my DD has always slept in the car, so it's something that works for me, it may not for you. And it's something I always hesitate to suggest, because it really seems like you're giving up everything to get a LO to sleep and also kind of a silly thing to do (like frowned on, iykwim). I guess, what I'm saying is to take this advice with a grain of salt! But, it has worked for me, and I've found that the car isn't really AP for my LO (meaning she doesn't get stuck on it, so once she's not OT, she goes back to sleeping on her own easily).
Otherwise, I think you just plug along with WIWO and maybe try somewhat set naptimes, so she gets used to it and starts getting the sleep she needs.
Another thing I wondered is if there are any signs of teeth coming in. My DD got her molars between 15.5 and 17 mo and she is a bit of a late teether, so it could be that Sophie is starting to work on those. Does she have any molars yet, or can you see anything back there in her mouth? It just seems like she's having a hard time, so I'm wondering if something else is bothering her.
Also, wanted to say I would have definitely gone and cuddled my DD if she had hit her face on the railing and her tongue started to bleed. We still need to comfort them when they need it! Poor little thing!
Sorry this got kind of long, I hope something in here helps. How did the weekend go?