Here's my incidentals list so far for a 5 nt/6 day trip with FD:
AirTran bags ($40/each way) - $80
Upgrade 2 AD tix 2 days - $30
CP OOP - $70
T-Rex OOP - $70
Tips for
DDP (4 ppl x 3 meals) - $45
Tips for DDP (6 ppl x 2 meals) - $36
Refillable Mugs x 2 - $29
Souvenirs - $200
DDs first haircut at Harmony Barber Shop - $20
TOTAL - $580 in cash
Our souvie number is small considering that we already have our ears. My only required souvies are silhouettes of the kids and an antenna ball. The rest is for DH to spend. I'll most likely beef that up to $650 in case we need to take a cab on departure day and I'm not 100% sure that we'll need two suitcases, but better safe than sorry.
We are taking our own stroller and gate checking it with the airline - I refuse to pay for the park rentals. You may want to look at an outside rental place, but honestly, your 1 yr old will do better in their OWN stroller. Check your local Goodwill/Salvation Army/garage sales for strollers. I found an old-style double jogger for $25 at Goodwill. Unscrewed the whole canvas part, washed it, and it looks brand new. It's already made 1 trip to the World. I found a bicycle gift wrap (it looks like an exceptionally large shower cap) that I use to keep it covered when it's not in use.
Are you planning to stay up for fireworks? I would get some glowsticks to bring with you (found at dollar stores everywhere). Disposable sippy cups, bibs, utensils - WDW only stocks big people utensils. I'm having 2 cases of water delivered and I picked up some flavor pouches when they were on sale a couple months ago. I'm going to hit up the dollar store for ponchos too. Whether we need them or not, again, I'd rather have them on hand!
I may get flamed for this, but I don't believe in tipping Mousekeeping. We really only have them in every 2-3 days to replenish towels and empty garbage. Shoot, on our last trip (4 days) we didn't have them in at all, I can't see leaving a tip for no services rendered. Now since we will be gone longer this time and we have planned time for the pool, then yes, most likely I'll leave a tip for our Mousekeeper. That'll fall into that extra bit I'm planning on.