I cannot come up with a new general rule that will give you the right answer in every case. Ser for permanent sates, estar for temporary ones, is the best I am aware of. But I can clarify most of your examples. Note that I'm from Portugal, and while I’m not aware of differences between Portugal and Brazil is this respect I would be surprised if there weren’t any at all. I hope this helps.
Location. Use ser for things that are intrinsically immobile. So a cozinha é aqui (you've got that one wrong), unless you're talking of a portable kitchen. Onde é a festa? because a festa takes place in one place. The festa itself is temporary, but while it lasts it is in one place. So the same applies to a reunião or a jantar and events in general. Now for the exceptions. Aqui está or cá está is an idiomatic expression used to show someone something. So I could drive you to the shore and say, with a sweep of my arm, aqui está o Oceano Atlântico, or, when showing you around the house, aqui está a cozinha (we use this especially for things of some significance, or when you’re eager to see the thing, so it should be some kitchen).
Health states/diseases. Use ser for chronical conditions, estar for diseases you expect to go away. So ele é diabético, because if you have diabetes you typically have it for life. Same with ele é asmático or ele é esquizofrénico. But ele está gripado because you expect the gripe to go away after a few days or weeks.
Occupations/hobbies. Never use estar. If you do not expect someone to keep some activity for long enough to merit the use of ser, you can say ele trabalha como consultor or ele está trabalhando/a trabalhar como consutor or, to give yet a stronger sense on transiency, ele anda fazendo trabalho de consultadoria. But never ele está consultor/escultor/futobolista. If he is a consultor then ele é um consultor even if he takes a break from it.
Young/old. You use ser as you know. I suppose that’s because that does not change overnight, and does not change at one’s will; you just age according to the laws of nature. Note that for inanimate objects we can use estar. O carro está novo if it is in top-notch condition despite its age. Same for a house or a shirt.
Dead/alive. You actually use estar mostly around the time of death or when someone might be dying, so when the state may be changing. Say, you arrive at an accident and ask ele está vivo? or ele está morto. If someone has been dead for some time, it is more natural, for me anyway, to say ele (já) morreu há seis meses. And you say ele ainda é vivo to mean that he is still living despite old age, but you say ele ainda está vivo to mean that he is still alive despite fear of eminent death, as in an accident.
Friendship. That’s perhaps the trickiest one. Maybe it is just out of an optimistic view of human nature: If elas são amigas they’ll be friends for life. We can say elas andam muito amigas to convey the idea that their friendship is new or unexpected or expected to be short-lived.