It is a phase.
She is 7 months.
Their cognition and motor skills also change. 6 months was a milestone period and growth-spurt period too.
Teething can also happen at this age.
They are just changing so much.
It will pass.
She is a light sleeper as you said, and every little noise, is now getting her attention and preventing her from lulling to sleep.
Try getting a white noise machine for her room when she naps.
She is on solids now.
Are you still nursing her, on-demand??? Even if on solids, a baby still needs to be nursed on-demand. Solids does not replace, nursings.
Then at 9:00am, you said she 'naps' for like 10-15 minutes.
WELL, that is just ONLY a CAT NAP, not a nap nap. That is not a nap. But then it is just enough, to then prevent her regular nap and interfere with it.
And then it is then, making her not tired, for her usual nap time... which you said is at 12:30-1:00.
A baby, should be napping 2-3 hours after waking. So if she wakes at 6:00am, her MORNING nap should be at 9:00am.
This is usual.
Her awareness of everything is changing too. She is reacting to everything she hears. And she is already a light sleeper. As you said.
My daughter as a baby, was very noise sensitive. Even a toilet flushing down the hall, would wake her. I HAD to make the house very quiet when she napped, turning off the phone too etc.
ALSO, my daughter, would NOT nap well, anywhere except in her crib. She also was not a portable napper.... not on the road or in a stroller or car. ONLY in her crib, she would nap. Same for my son.
Also, teach your son, to "whisper" and tip-toe... when it is baby's nap time.
My daughter was 3 when I had my 2nd child... and even at that age, she completely UNDERSTOOD, that her baby brother's nap time, meant QUIET.
Teach your son not to call you when you are putting baby to nap... but instead, to TIP-TOE, and come to you whispering.
My daughter would do that, and she was 3 at the time.
My son was still napping 3 times a day, at that age. For 2 hours each.
Your daughter is 'cat napping' because her naps are being interrupted, by noise. And the activities in the home and the cats.
And, she gets mad when you walk away... because this is the age when 'separation anxiety' is developing. My son and daughter, had that at 6 months old. It was also per our Pediatrician.
So, now that she is a different age juncture, you have to, tweak your nap routines for her. Her cognizance and awareness of things in the house, is more heightened now.
Over-tired babies, actually fall asleep worse, or cannot fall asleep or they wake more.
Your baby is only getting 1 nap a day????