for the first question : at the end of your contract they give you the caution they took at the beginning, they pay your return to your country, and your last month of work
then it's 300€ per person and per month to live in their housing directly taken on your salary but some helps exist to pay less
finally disneyland paris is in france, most of the visitors are french speaking so you need speak french and understand it a little bit. english is needed too to speak with other visitors (all the attractions are both in french and english). european languages are liked and other languages are used for "rare" languages (polish, russian,...)
sorry for my english,
n'hésitez pas à faire un tour sur la chaine youtube de themeparks voyages
https://www.youtube.com/channel/UCu7b4elLrO-tYXmM0xIj5IA
et pour voir les autres publications cliquez sur les icônes ci dessous ;-)