Hi Adam John,
In order to try to obtain an answer to your questions, I sent an email to Disability.Services@DisneyParks.com with your queries and received the following response:-
1/ There are 2 wheeled bicycles as well as 4 wheeled bicycles located at Disney's Boardwalk Inn. There are no straps to my knowledge.
2/ I recommend bringing your own waterproof protectors as the linens at the resorts are the traditional type. I recommend checking with the Front desk upon arrival for better communication for any special requests regarding the linens in the rooms.
You can read more information about
Services for Guests with Cognitive Disabilities on the Walt Disney World website.
I do hope that this information has been of help and would definitely recommend that you send an email directly to Disabilities.Services@DisneyParks.com should you have any other queries or require any further specific information.
Wishing you a magical holiday filled with memories which will last a lifetime!
Emma