Right sweetie here goes:-
1.
It is entirely up to you!!! 'Just Marry' have preferred vendors with which they work frequently and trust. You can either book them (and they will work with you on the details to get what you want) or you can research and book your own vendors. I did a mixture - I booked my own officiant, photographer, musician, cake-maker, hair and make-up and reception. I went with Karen's advice with floral and transport. I was going my own way with floral too, but that didn't work out!! Whether you choose your own vendors or use 'JustMarry''s recommended ones, Karen will have all their numbers and is happy to co-ordinate with them on the day, but obviously JM will take no responsibility for the work of vendors you book yourself!!! Mine all worked out perfectly!!
2. Costs vary enormously according to what you want, location, number of guests etc. My advice would be to get a rough idea of how many guests, when, what you want etc and then drop JM (or Karen if you are already in contact) an e-mail.
3. The same rules (and prices

) apply to S/D brides as to DFTW brides as regards characters. You can have the same characters attend under the same circumstances as DFTW brides. You do not have to have a reception at Garden Grove to achieve this.
4. You can still arrange a dessert party through Disney, however it should be arranged through the events department rather than DFTW. You should say that it is for a 'family gathering' or 'celebration' when booking and not a wedding as if they think you are booking for a wedding, you will be referred to DFTW and up go your minimums!! You can wear your wedding dress to the event if you chose a 'Wishes' DP, as it takes place at the GF and not in the MK. If you chose an in park DP (Epcot or DHS) you would have to change out of bridal attire for the event.
5. You can have a bridal session in any park except MK - a session in bridal attire at the MK is a privilege reserved exclusively for DFTW brides. Whether you are a DFTW bride or a S/D bride, you need to use DPS for such a session as outside photographers are never allowed in the theme parks.
I wanted something completely in contrast to the more formal pictures on the VR day, and so we had a TTD session with Randy at the Poly a few days later - we shot in the Lagoon, on the beach, at SP and in the pool. The result was some of my favourite pictures of the whole trip, and it was great fun!!! It cost me about $200.00 (excellent value!!) and was an excuse to wear my dress again!! My dress is now cleaned and as good as new. It didn't really get 'trashed' at all!!
6. Again, it is up to you. I booked the 'bare-bones' minimum package as I wanted more control, and added my vendors and details as I went along. My package included venue (West Courtyard), chairs, water station set up at ceremony site, rain back-up location, suite to get ready in (if required), use of flatware, glasses, plates etc for the cake and champagne pre-reception and all Karen's excellent services for planning the event and co-ordinating the day. JM offer various different packages which can include as much or as little as you want!!
I won't even pretend to be an expert on 'Escape' packages, and I am sure somebody, with knowledge far superior to mine on the subject, will be along to help with that one!!
Please feel free to check out my PJ/TR (link is in my signature) and don't hesitate to ask if you have other queries or questions!!!
HTH and good luck with your decision!!