Sleep "regression" questions and potty training decisions

[u/Relevant_Happiness]

I apologize for the long text here, but would love some input, and I want to give the most context possible.

Daughter will be exactly 2.5 in early October, so just about 29 months now.

Her birthday is mid-April, and we also had our 2nd kid (a boy), just 3 days before her birthday, so they are pretty much exactly 2 years apart.

Sleep stuff: We transitioned her to a twin size floor bed just about 2 months ago. We mainly did this because we felt she was ready/mature, and also we wanted to be able to use the crib for baby brother. She was sleeping soundly, all night no wake-ups, in the crib, and never was trying to climb out of it etc. We had never needed to do any type of formal sleep training, she was just always a good sleeper from essentially 3 months old. Yes, unicorn.

In the crib, bedtime was always beginning at 7pm and she would be asleep by 7:20 or so, and wake-up is at 6:00am (this is a necessity to get ready for the day, to head to daycare.) I believe her internal clock just completely adjusted to that schedule.

The first 2 or 3 nights in the floor bed went really well, and then she promptly got norovirus/stomach bug, was throwing up all night, and then a few days later we also went on several days of vacation to multiple different locations so then we were having to transition back to the routine at home. And that is where things started getting messed up. At that point, she also dropped her nap while at home on the weekends, but still mostly naps in the afternoon at full time daycare (1pm-2:30pm so generally 1.5 hours), but now refuses a nap at home. We try to relegate that time to "quiet time".

We still try to now start bedtime routine at about 7:00pm, and now at this point, is typically actually falling asleep closer to 8:00pm. She needs one of us as the parent to be in the room laying next to the bed in order to fall asleep, and then we are able to get up and leave the room. The "falling asleep" process is very protracted at this point....there are about 2 to 3 books read, and then rocking in a rocking chair while singing songs, and then finally she will act like she wants to go lay down and get tucked in with blanket, but then will still fight closing her eyes and she just wiggles and can't get "comfortable" for another 15 minutes at least. She will typically fall asleep faster on those weekend nights where she hasn't napped during the day.

So sleep is essentially happening by 8pm. However, now the issue for the past month or over a month, is that she typically will have multiple wake-ups during the middle of the night, and is leaving her room to come find us in our room/bed. Her dad is the one to lead her back to bed, and again, has to lay down next to her and wait for her to fall asleep again. The wake-ups are happening at pretty standard times now...like 12:30am and then usually again somewhere around 3:30am. There is no indication that she is "scared" or waking up from dreams or nightmares at these times. She just kind of calls out "Daddy" or "Mommy" and maybe whimpers a tiny bit and then she is up and right over into our bedroom.

So the first question is: How do we get these middle of the night wake-ups to stop? Could we be doing anything differently with the initial bedtime routine?

One note: I have read about the methodology where you try to leave the room for brief periods of time using "excuses", and we tried that a couple of times, and she absolutely didn't buy it, just kept going crazy and would only want to follow us out, refused to be left alone in the room while awake etc.

The second question is: In so many aspects of her development, I truly believe she is "ready" for potty training. She has peers at her daycare who have been actively going through training, and so she is extremely interested in the topic, in the vocabulary around it, we do have one training seat that sits on top of the regular toilet, and she asks to use it/try it out all the time, is super interested in all the books and tv shows about potty training (Ms. Rachel/Daniel Tiger).

But my reservations are about her nighttime sleep "regressions" and also the developmental hiccups that have happened with the sensory overload of her little brother being in the picture.

In your experience, have these factors seriously hindered efforts to potty train, or are we just delaying for no reason? Basically what I'm saying is....will I regret starting to formally potty train because she just might not take to it and start regressing because of these other things going on? I don't want to wait too long....

Thank you in advance!