My 2 siblings and I are the co-executors of our dad's will.
He has a couple of IRA's, personal savings accounts, a stock trading account, and then he has a partnership that holds some property and maybe some trust funds set up. The assets are going to be divided up equally amongst the three of us.

My question is, is it better/simpler to set up an EIN for the three of us for an "estate account"?

Or... do not use an EIN and instead use personal accounts?

I have no idea what to do, and after talking to my dad's lawyer, his accountant and banker, I'm even more confused!!!

I got an EIN. I think the estate account made things go smoother and cleaner and is more transparent . Bank employee walked us thru the process on the government cell phone app and we had a EIN in less than 10 mins. I see no downside .

You're likely to have both income from rmd's and perhaps stock dividends , etc and your'e also likely to have bills to pay and maybe real estate to sell. It's an easy repository for income and easy to pay bills from an estate account . You'll also need a place to hold money until all past tax returns are filed. It made all of that easy.

Another tip on the Ira's . You and your siblings will want to set up inherited Ira accounts for each of you and there's some paperwork requirements to do so. You can't just dump inherited Ira's into your personal Ira's because your'e required to take rmd's out of inherited Ira's on a schedule that's different from your Ira. I didn't know that in advance but the Ira custodian won't distribute the Ira until you do it. You can take it as cash but it's taxable the yr you take it

We got one for my FILs estate but it was mostly because there was going to be ongoing income. If it can all be closed out this year, maybe you don't need it. Definitely need good advice.

get an EIN for the "estate of (your dad)"

you'll need to file a final tax return for your dad and then one for the estate of your dad after everything is settled

Account(s) with funds coming from an estate account with an EIN are much easier to keep the IRS out of your business. No IRA custodian is going to distribute IRA holdings to a beneficiary without a new inherited IRA to put the funds into, plus if there is an RMD due they are going to distribute that as well. They should also ensure you don't screw up the 10 year distributions. If dad had an FA he/she should know all of this and can save you a few hours worth of attorney fees. The FA can also set up your EIN.

That partnership share may be a little difficult to deal with for estate purpose. If this is a real estate investment you will likely have to get a fair value assessment on that. Another note, co-executorships can be a pain unless everyone is in total complete agreement

I read past the mention of the partnership in the OP and don't know how much of the partnership your Dad owned or the basis and value of the real estate, but you will want to be sure your CPA discusses with you the 754 election.

The banks and be other financial companies are going to require an EIN.