We love DLR in October and go during that time yearly. We love OBB as well. While we go many different times of year (always school holidays or summer, so busy times), October is particularly crowded. Everyone loves Halloween, and Disney does it so well!! That said, you will really need to adjust expectations if you are coming during that time with small kids, a stroller, grandparents and are wanting to be able to eat full breakfast in the hotel and not make rope drop (and I assume not stay late until MN either with small kids). I know it is a mess trying to get young kids and grandparents (and hangry husbands!) out the door for rope drop! That said, it is your best time of day to try to get through some rides without terrible wait times. As well, even if you buy G+, you can’t book a LL for a ride until each person in the party has scanned into the park for that day (ie you can’t scan in at RD while everyone eats breakfast at the hotel and then you make everyone a LL). By the time you get to the parks after breakfast, lines will be starting to get (or will already be) long (think 1hour+ for many rides and 1.5 hr+ for headliners or more) and LL return times will be stretching out into the afternoon already. The value of G+ diminishes quickly if you aren’t able to start booking in the morning (due to LL return times pushing out, as well as the 2 hour block out between bookings; see the Sticky about G+ for more details). I have never used
DAS, so I can’t comment on how that might work if you arrive to the parks mid morning.
Crowds will be thick, but the stroller sounds like it will help the kids. What about the grandparents in that scenario? Dining with 6 ( or even fewer) can be a challenge if you don’t do TS (which adds up in expense quickly). You can do QS, but make sure to Mobile Order your lunch in the morning so that the return times for MO don’t start to move out on you (that is, you decide to MO lunch at noon, but the first slot for MO is an hour away or longer). Finding a place to sit and eat can be a challenge when the park is crowded as well, so try to eat at off times.
We love OBB, and yes, you can enter at 3pm with only a party ticket, but know that regular day ticket guests can usually stay in the park until 6pm, when the party starts. So 3-6pm can be really crazy busy. Once the party starts, there is a lot to do! If you are using that only to ride the rides, you won’t have much time for anything else (parades, treat trails). If you do the parade and the treat trails and Villains Grove, you won’t have much time for rides (especially if your kids can’t stay up and keep riding/going until the party ends at 11pm). G+ does not work during the party hours, though I think it works during the mix in time. You can buy an ILL$ during the mix in time. IMO you can’t do DCA justice by only going to the party, so we always have a regular ticket that day too, but that adds a lot of cost.
You can still make a great trip out of it when it is like this (we always do!), but you have to have a plan and be ready to not get everything done. Have some priorities in mind, and count the rest as gravy. If this is not the type of trip you will be happy with, I would definitely come back in the summer. Crowds are actually much lighter at that time.