Congratulations! We got married at the Wedding Pavilion back in 2016 and there was 26 of us so we have similar numbers to you. We had a reception at the Grand Floridian and then a private Fireworks Dessert Party at the Marina - truly was the best day ever. If you have more than 20 guests you will need to do the Wishes package which is completely customisable and anything under 20 guests would be their Escape package which doesn't include a reception as such, but you could still book yourselves into a restaurant somewhere (go for a resort restaurant as I believe you can still wear your dress)
If you are interested in the Wishes package, you can call them at 16 months prior to your wedding date to get the ball rolling with them and then your date will be secured at 12 months, and Escape packages I believe you can contact at 12 months and they will secure your date at 9 months (might have changed as it's been a few years and it seems to change all the time) - unfortunately they won't speak to anyone outside of these time frames, and like you said the website isn't the best. They will give you approx pricing throughout your planning but they will confirm the final cost at 6 months out. We just gave them a call at 16 months and took it from there, and once we had our date secured at 12 months, we then booked our flights and accommodation. They make the planning really easy over phone and email and we couldn't have been happier with the way everything went on the day, really was a dream come true.
Any questions, just let us know, and yes like GirlDreamer said the Wedding boards will give you tons of help too. Enjoy your planning!