I think u r talking about gold. It's a good time for gold. I know apmex is accepting Bitcoin, they are a gold dealer, I think they have a deal for btc users, check them out

I think it should be in cash. Bitcoin will have a greater role.

Bitcoin once converted to cash should be declared for tax purposes. If you already have enough cash at hand, then it would probably be in your best interests to buy with cash. I know certain countries do not charge tax when cashing out bitcoins, so may be in your best interest to cash out there instead. I also know that in other countries holding bitcoin is known as speculative gambling, so if you've held it for over a year it is also tax free.

No, I would rather hold bitcoin now and not sell. If I were on your shoes, I would rather used cash to buy the bar and do not touch your bitcoin this early. Bitcoin has peak at $19,000, I'm sure that we can get it there again, if you sell at the current price your potential profits is gone. I don't know where you lived, but definitely when your convert your bitcoin to fiat, there will be tax issues that you will encounter in the future. So to make things easy for you, just used the old traditional fiat of yours. Goodluck to your new endeavor. I myself have offline business though (but not a bar).

this part is the key in my opinion. it depends on how much bitcoin you have and how much of it you are planning to use. for example if you are only using 50% of your stash then it is a good idea.
you can even try to buy it directly with bitcoin and then put up some bitcoin signs in your bar, it can help getting you  some publicity. you can call it "Satoshi's bar" or something like that

I can't talk about tax since I don't know where you live but have you already worked out the total cost for the business? Are you building the bar from the bottom-up, buying a property and converting it, or are you buying an existing bar?

The less btc you have to convert, the better. Maybe just enough for fixing the place, for the utilities/maintenance/salary, etc. Preferably it is on installment so you can just convert what's needed to pay for a year and just hodl the rest.

I also think this will be the best. If you own such a capital, then gold will be the best choice. If you want you can cash it out or anything else.

if owning a bar and running it is something you like as you said "it is something i wanna do", then go for it. you don't have to sell all your bitcoins. sell some of it and get the rest from fiat.

you can even use your bar to earn bitcoin!
i would seriously think about this if i were you, you can start accepting bitcoin payments or even design a nice QR code for "tips" in bitcoin and hang it up above your bar.

The government is afraid bitcoin is used as a crime tool. many crime cases occur using bitcoin.
this is an issue that hinders the development of Bitcoin in various countries.
I will hold some and then sell them into an asset like gold. it's wiser

Afterall, cash is best of all. It's easy converting bitcoin to dollars and then make a purchase. There will be fewer questions and mistrust. So that's that.