Is there a minimum amount to set up an irrevocable trust fund?

There is no minimum as just about any asset can be titled in the name of a trust (such as a bank account with $100). The question I would ask is why is the trust being established and by whom?

Assets transferred to an irrevocable trust are considered uncompensated gifts for Medicaid eligibility purposes subject to the famed "five year look back".

I don't believe so. The trust has to be set up first and then you can transfer any funds into it. We just did this for my Dad. We started with a certain amount and then will eventually put more money into the irrevocable trust.

There are all kinds of trusts and you really need to understand what the "trust" is. Also how it is going to be funded and maintained for the years and years ahead.