My daughter doesn't have curly hair but does LOVE to pull out any ponytail/braid I may put in. She does have a ton of hair so we struggled with the same knot problem. My MIL found THE WORLDS BEST ponytail holders!! They are for adults and not in fun colors but work sooo well!!! They have a spiral of rubber around the band that keeps it from easily being pulled out, or slipping out during sleeping. My daughter would try to pull it out but it was so hard to she pull more on her hair and it would hurt. So she just gave up!!
You can find these ponytail holders at any walmart! Worth a shot!
Also, have you tried an adult detangler/leave in conditioner?

One of my 2 year olds has curly hair also. Luckily its doesn't get that bad all the time but sometimes it tangles horribly. If you find a solution let me know.

Look for a Duboa brush. Since you have curly hair as well, you might appreciate it as well. Detangling combs are also useful. Both pull out tangles without pulling the hair or hurting. They both are so well made that they won't need to be replaced for a very long time. I found them on ebay, but I believe they are also sold on amazon.com.

http://cgi.ebay.com.au/MEDIUM-DuBoa-Hair-Brush-Made-in-Japan-choice-of-colour_W0QQitemZ330420512913QQcmdZViewItemQQptZAU_Hair_Care?hash=item4cee98e891

http://cgi.ebay.com.au/Ceramic-Tools-Detangling-Comb_W0QQitemZ250537748048QQcmdZViewItemQQptZAU_Hair_Care?hash=item3a5536a650

I like Johnson's No More Tangles

My son has very curly hair and I do not want to cut it off. I think it's beautiful. I finally resorted to using my conditioner and combing out his hair while he's in the tub while the conditioner is still in his hair. I start with a pick to get the big tangles out and work my way to a brush. It's slippery but it seems to work for curly baby hair.

My daughter has curly hair, I use pantene or dove conditiors it seems they are the only one that doesn't seem to dry it out and keeps the soft and not brittle.
I wet it every morning and brush it out and if needed use detangler. then sometimes use a small amount of curl mousse from pantene. it helps the hair not tangle in the day.
Don't use to much then it looks wet and clums together but it I use a pea size amount it keeps the curls looking cute and not frizzy.
she has short hair too.
Just keep trying the hair things it you want it it will take time for her to not pull it out. I just use a clip for the bangs.
at night hair is crazy in the morning. can't get away from that or after naps.

I just found this leave in conditioner spray that is AWESOME...its for adults but I LOVE IT. Its called "Its a 10" (mircale leave in product) I just gave birth 6 months ago and between the pregnancy and birth my hair was completely wrecked...this stuff has just helped so much...it smells AWESOME and it detangles great and it leaves my hair feeling great. Its a little pricey but my hair is pretty long and the small bottle is lasting me a long time. I would totally give this a try.

My 2 yr old also has the same problem. I wash her hair with baby shampoo and use adult conditioner as well. I comb the tangles out while shes still in the tub and the conditioner is still in her hair. Then I rinse her hair and when its soaking wet still i put some frizz ease in it. It will be sleek and shiny and most likely tangle free in the morning.It works pretty well for her and combing it out in the tub gives you the option of destracting her with tub toys. I hope this helps:)