When to pay the bills?

In your situation, especially if you co-mingled your money, is see a lawyer. In the meantime I would allow utilities to be paid. Maybe getting the co-executor involved too.

Dh was FIL's executor and began paying bills immediately and closing accts at the same time. Some places needed to see the death certificate, but that wasn't a problem.

It can take well over a year to close out everything, so be cautious how you pay out things, making sure you don't have to 'negotiate' some bills. Dad has stuff coming in a year after he passed--some worthless property we can't sell, but have to pay taxes on every year.

There's really no rush, unless you want there to be. So many emotions swirling around right after the death of a LO. Take your time.

I was on my dad’s checking and savings as an equal owner in the eyes of the bank. I did pay bills immediately with no issue, no estate account needed. I’m sorry for your loss and wish you peace

I am assuming you may want some of these things to continue, and some to expire. For instance my own partner has some of his own bills coming out of the household account, ie his phone, and some of the household bills coming out, ie the computer-phone-TV bill. You should notify the companies of those wills you don't want withdrawn. Most accounts that are joint stay active in your name only; only a few are temporarily frozen for recover of a social security check during month of death.
Do go to a good Lawyer to help you walk through settling the estate. This is so worth it. I paid for about one and one half hours of lawyer time for my brother, and it was invaluable just in terms of getting the EIN number for the Estate quickly.
Wishing you luck. Take it a day at a time. And I am so very sorry for your loss. I will leave with recommending a short and easy book you can get from Amazon. It is Please Don't Die, but if you Do Die, What Do I Do Next. A paperback written by Kurt J. Grube.

I am sorry for your loss. I hope this article helps a bit:

https://www.elderlawanswers.com/what-happens-to-your-debts-when-you-die-14689#:~:text=Usually%20your%20estate%20is%20responsible%20for%20paying%20any%20debts%20you%20leave%20behind.&text=The%20person%20who%20is%20appointed,any%20money%20passes%20to%20heirs.