All three are capable of handling their own finances. The one with a history of addiction could always relapse, but is quite stable at the moment, and I’m reluctant to single him out as the only one needing to have his money controlled by someone else. I could put everyone’s inheritance into a trust but I’m likely to outlive any responsible family member who could be trustee.
I would likely recommend setting up a revocable trust (and pourover will) for yourself, consider putting your assets in the trust during your life (not the retirement accounts, which must be owned individually), consider naming the three kids as equal beneficiaries at your death, and have each of their shares be held in trust with distributions at the discretion of the trustee. A good trustee can decide at that time, perhaps with some financial, legal, and/or accounting advice, whether to pay out the beneficiary's share or to keep it in trust and pay it out over time. A good trustee can take into account whether any distribution would affect any benefits the child receives or whether addiction is an issue.
The bolded part above is the sticky issue you and a lot of other people face. Some of my clients who have good relationships with their exes choose to name the ex as the trustee for their common children. Others name family members and friends in a list, sometimes 5 people deep. Others opt to name a bank or trust company, but they have to be careful to find one that will take on a smaller trust. Sometimes they can be named as a co-trustee to serve with a family member or friend. That way the friend can assist but not be fully responsible for all paperwork (tax returns, accountings), and the friend can also point to the trust company if they want not to be blamed for not making a distribution or something. But of course the bank will take 1% or more in assets under management annually.
I will say that I would not leave the house to just one child, and I would not leave specific instructions about whether to sell the house or not, as you cannot predict what will be the best route at that time. If you name them all as equal beneficiaries, then at least they would each have equal rights.
As for the retirement accounts, I often have clients name adult children individually in percentages, and that way the children can turn the IRAs into their own "stretch IRA," but if any of them may need to receive government benefits, I would talk to an elder law attorney in your state to determine if owning an IRA would interfere with those benefits. Also, know that if you name the child as the bene of an IRA, they may not choose to stretch it but may choose to cash it out and pay the tax due--and if they are suffering from an addiction, then it's all gone. So in that case, it may be better to name the trust as the beneficiary and lose the ability to stretch it. Protect them from themselves.
I almost NEVER recommend leaving specific assets to specific people because what you own today may change tomorrow. I handled an estate where someone had specifically left one account to one niece and another account to another. Then she liquidated one of the accounts to get a better rate, and she died before she could rewrite her Will. So the niece who was supposed to get that account got bupkus.