For a reference on making water buffalo check out the Navy Seal diorama by csago in the diorama forum from early December 2004. Type csago in the advanced search and search by author. Then click on csago's user I.D. and it will link you to his posts. He converted a Dragon/DML Donkey into a realistic water buffalo, dripping chin and all.
As far as all the other questions. There is a booklet you may be able to find in the local library that covers farm carts constructed in miniature. I bought a copy from eBay awhile back and it is a neat book to have in the reference pile. I will dig it out and get the ISBN and Author for you.
Secondly to make bamboo another great reference is Model Buildings Masterclass by Roy Porter it shows an easy way to make bamboo out of the long side pieces of sprue left over after the kit has been removed with three every day tools. One miniature Swiss file, a power hand drill with adjustable chuck and a piece of sheet metal. It works really well and you can make as many lengths and thickness you want.
Cheers;
Gregory