HA! I KNEW it wasn't your friend who didn't want to sign a lease...it was you. And now you want our advice on how to screw this LL who was quite trusting of you and who you are now being unreasonable with.
If LL lives in the same apt., I doubt there's much than can be done about the heating and cooling issue. Cooling is generally optional, and therefore you have NO standing in this regard. Heat must only be kept to a safe level. Unless you sustained frost bite from him turning off/down the heat to save energy and money, you probably have no claim.
Blinds are also generally optional. Unless you can PROVE he promised them, your case is quite weak.
No furniture? So you eat, sleep, and sit on the floor? Furniture is also optional, again, you would need something more than you saying "he told me he would give me furniture." IF you had the original advertisement for the room that said furnished you MIGHT have somewhat of a case.
What is wrong with the hot water? Generally, unless you get NO hot water EVER or you have NO control over the water temperature AT ALL (i.e., you can't avoid being burned), there's nothing to be done about that. If it takes a long time to heat up or needs a little "messing" to get it to the right temperature, well, those are just typical features of a lot of houses.
Do the "geese drops" prevent you from using the garage? Unless you actually live in the garage, I really doubt there are any rules about sanitation out there. If you physically cannot use the garage and he charges you for it, you have something. If you have to wipe your shoes off after leaving the garage, you have nothing. Also, have you tried closing the garage door? That'll keep the geese out.
