Hey hun!
Congratulaitons and welcome!
Realistically, I think for 100 guests you are going to far, far exceed $20,000. But, remember that guests cannot make the trip for various reasons. We budgeted for 100 guests and only have 70 coming. I am answering your questions because your desires sound very similar to what we went into planning mode wanting.
Your weeend wedding minimum expenditure is going to be higher than doing it on a week day. I believe the minimum for weekend weddings at WDW IS $20,000. We are weekday and it is a $10,00 expenditure. Believe me, we have no trouble meeting it.
A dinner reception with a cocktail hour is going to cost you a pretty penny. Dinner off the bat is more expensive. it sounds as though your looking for a seated dinner to me than a buffet. If so, you should estimate your dinner costs at about $100 per person after tax anf gratuity.
Alcohol at Disney doesn't come cheap. No way around it. Also for a pre-reception, you're almost guarenteed to be hosting the bar. Please PM with your email address if you wanted the bar prices for WDW hosted, cash, and wine selections. Champagne toasts are very expensive, as well. They pour about 8 glasses per bottle. I believe the cheapest bottles are around $25 a piece before cork fees, etc. For those not of age, the Martinelli's cider is about $30 per bottle after corking fees. I realized how outrageous this was after I saw a bottle of Martinelli's cider at the store for $3.58!
The elegant atmosphere is going to be most determined by your venue, decorations, and lighting. For us WDW brides, the Grand Floridian costs a lot more per person for dinner than the other function room options. It doesn't necessarily mean it's more formal, but fits your budget, style, and taste. For decorations, the option are endless.
The largest chuck is going to be your floral budget. I will be honest, our floral is over $5,000- 25% of what you're budgeting for and our's is 70 guests. We don't have many extras either; nor are our centerpieces that expensive individually. The extra we did splure on in the floral department were the rose petal cannons. Remember you can cut costs by using greens and in-season flowers. Also, we are using our centerpieces to line the aisle in the Wedding Pavilion. There is a $100 change fee to get the flowers to the Yacht Club and into the dinner time candelabras.
Also in your floral estimate are your linens. White and black linens are provided by many of the resorts. Anything other than that and you are paying. Chair covers are another biggy. We included them and chose to have them because we are having a black-tie wedding. You may want to keep that in mind when selecting your wedding colors. We ended up at a black and white wedding by default, really.
For decorations, you have endless options. And none of them come cheap becuase of the labor involved. The landscaping package can help bring down the ceilings and create a more intimate and less sterile room. I believe the packages start around $1, 400. The tulle canopy with lights is in the neighborhood of $1,900 becuase of the labor involved with getting it hung.
Your cake's price will depend on the cake you choose. The mini cakes are the most expensive when dealing with large groups. Unfortunately for us, we chose th emost expensive cake. Oops! Your number of guests will also play with the price as you are charged per person for the size of the cake. Also involved are cutting charges and plating fees. I would estimate most Disney cakes for a larger Disney wedding (70-100 people) are going to run between $1,500 and $2,000 when it's said and done.
Your DJ package is going to be expensive. Disney has managed that. They will run about $1,300 for a fairly standard package. And no, don't think about bringing someone else in. You'll have to pay $700 to have Disney set up the dance floor and allow them in anyway. Your DJ's package includes the dance floor, dance lighting, spotlighting for your headtable and cake table, and gobos for the walls. Gobos are projected light images that swirl (slowly).
Your string quartet through Disney is also expensive. Any musical or acting talent is. For us, coming from very musical families, we have been able to bring in talent. The only fees we are paying to Disney is a $200 tuning fee for the piano becuase it must be moved. You can have family or can find talent, I would suggest doing so. We have paid for car rental, 2 hotel nights (for the road- one night on the way and one night on the way back), gas, and toll money for the talent we have brought in. For the Wedding Pavilion in WDW, having a string quartet at the ceremony seems like a waste of money when the organist can play the same piece with the same instruments on the organ for the already included fees.
This isn't meant to scare you. But I did want to give you a realistic view of Disney World wedding prices. The Wishbook is great although not always accurate. For example, the centerpieces were the floral department going crazy. In all likelihood, it's not going to cost you $600 per table for chargers, floral, linens, etc. You need to sit and have a talk with the parites who will be responsible for paying for the wedding and find out what their budgets are. Remember, you almost always go over what the said budget is... try to remember that when you do talk with family or between yourselves. Also remember you may have to give and take where you can for your dreams to come true. At the end of the day, the most important thing is that you have one another and have solidified that covenant for God and family.
Good luck!
xoxo