So October is still a little bit away but, I tend to be a bit of a perfectionist and I will be doing as much as possible myself so I want to have time to pull it off. Now for the brainstorming criteria:

I am a young mom in my mid 20's. I have a little girl and am expecting a second girl very soon. By the end of October my 2 girls will be 19 months and 1 or 2 months old. I'd like to do a theme something for the 3 of us if possible but I don't know what would be cute. Any suggestions would be most helpful :3

First off, congratulations on your new bundle of joy!! :) An idea that comes to mind would be you as a witch, your older daughter as a kitty, and your newborn as a pumpkin! :)

Congrats! :) My first thought was a candy theme. You could make a box/package of your favorite candy for you and dress the little ones as candy. For some reason I'm picturing cute little gumdrops, haha.

You guys could go as eggs bacon and pancakes lol. I'd try googling baby halloween costumes...I see people have made their own spaghetti and meatball costumes and everything when I googled.

You could dress up like icons on an iPhone. Facebook, twitter and snapchat? It would allow you to wear as much or little clothing under it in case the area you live in warm/cold that time of the year.

There are some super cute ideas on pinterest!

You could also go as one of the classics...family of pumpkins, ghosts..etc :) Those are always easy/inexpensive options!

I'm thinking koalas or kangaroos...

you could do a pokemon line with 3 evolutions. Example: you dress as Raichu, your older daughter as Pikachu, and the new baby as a Pichu.

Well, I'm pregnant and there's the phrase "A bun in the oven" So I'm going to dress up as an oven with a bun on my belly and my existing children are going to be other baked goods. Some altered form of that might work out for you. OOh, or .. have you ever heard of cabbage patch kids? You could dress up as a larger form of doll and dress your two children up as cabbage patch kids, the stroller/strollers could be made into boxes for them. You could go as a mother duck with her ducklings in a row. :D I'm really into Halloween.

Family of ghosts sounds good. Or you could all be cats, that would be super cute. There's also some sweet ones that are superhero costumes. Google 'family halloween costumes', there are some really good ones

I just have to say that your idea of being an oven and your other kids are baked goods, is totally cute.

I saw this on pintrest today and thought it was super cute. You could maybe be a vine and dress both of them as strawberries? Or you could be a tree and one could be a leaf and the other an acorn. If you like Despicable Me, you could be a character from that and your kids could be your minions. Or maybe a chicken with a young chick and a not-totally-hatched egg? Or Pirate/parrot/bag of treasure?

Maybe a Thing 1 , 2 & 3 idea?

I'm all for the koala routine. You can be a eucalyptus tree and your lovely girls can be baby koalas!