Welcome to the DIS!!!
Since your DD is only 2 you do not need a park pass for her. She is free. Also if you do a character buffet she is free too!! That would be a great way for her to meet characters without waiting in long lines! At DHS(Disney Hollywood Studios, formally MGM) she can meet the Playhouse Disney characters like Little Einstein's, Handy Manny, JoJo. There is also a really cute Playhouse Disney show there. At Epcot there is a great character greeting area that is indoors and you get to take a picture with all the classic characters one right after the other!(Mickey, Minnie, Goofy, etc..) MK has the Judges tent in Toontown where you can meet all the classic characters and princesses too!
Make sure you plan enough time for transportation. Most off site rentals that say they are "10 minutes" away from Disney are usually referring to Disney Property, not a specific park. For example if you want to be at MK at park opening, leave yourself way more than 10 min. to get into the park. Once you are actually at the MK, you have to park, ride the tram to the TTC, then board either the monorail or ferry to get to the MK gates.
Try to make a general plan of which parks you want to do. We can easily spend 2 days in Epcot(which is my kids favorite, they are 10 and 5) and 2 days at the MK, followed by 1 day at DHS, and a half day at AK. I assume you will want to take it easy with a 2 year old and possibly one on the way so a good plan will help.
My best advice is to read these boards until your trip! You will find so much great information.
Oh, remember the more days on your pass, the less the price increase. I believe the difference in price for a 5 day hopper to a 6 day hopper is only $3!!
If you plan on 1 character meal a day then get on the phone and make those ressies now! May can get busy and a lot of people have already booked their meals 180 days in advance. I would head over to
www.allearsnet.com and look at the menus and decide which meals you'd like to do, then call and make an ADR. Some great ones ar Crystal Palace at the MK for lunch(Pooh and friends), Chef Mickey's at the Contemporary resort(Mickey and friends).
Let me know if you have any other questions! I'd love to help. We have been going every year since my DD was 9 months old, now she is 10!!