The usage of "will" as the future-tense marker rather than to want is an oddity of English, not of German. In Eald Ænglisc the word "to want" was Ƿillan with the Ƿ being an archaic symbol for W. In Swedish to want is "vilja", in Dutch it is "willen" and of course in German it is "wollen".
No, it isn't, for historical reasons.
The same ones, incidentally, that make it "she will do it" in English and not "she wills do it" with -s on the verb.
A handful of verbs have no endings in the ich and the er, sie, es forms, e.g. ich will, er will; ich weiß, er weiß; ich kann, er kann.
In English, this is mostly the modal verbs (he can, he will, he shall, he must, etc.); in German, it's those but also a couple of others such as wissen.
Nope. As Luis Domingos said. Käse does have a figurative meaning in German, but it's nowt to do with money. "So ein Käse!" means "What a load of rubbish/nonsense!".
However, just like in English, there's a plethora of other words used colloquially to mean "money". For example:
Die Kohle (lit. the coal)
Das Pulver (lit. the powder)
Das Moos (lit. the moss; and there's also an expression "ohne Moos nix los")
Die Kröten (lit. the toads)
Historical reasons -- the same ones that are responsible for the forms "she can, she will, she may" in English as opposed to "she cans, she wills, she mays".
(Basically, the form evolved out of a past tense, and those don't have any ending in verbs such as "she saw, she gave" or sie sah, sie gab -- and thus it is sie weiß, sie will, sie kann, sie muss, sie mag etc. without ending in German and "she will, she can, she must, she may" etc. in English. All of them are modal verbs in English and most of them are in German, too, but wissen "to know" also joins that group.)
All those verbs have no ending for ich, either -- just as it's "I saw, I gave" and ich sah, ich gab, so it is also ich weiß, ich will, ich kann, ich muss, ich mag etc. and not ich weiße, ich wille etc.