Excepted estate query where residue passes to FLIT

I have a query regarding whether an estate I am dealing with can be treated as an excepted estate.

Husband died leaving a will including a NRB discretionary Trust with the residue passing into a FLIT with the surviving spouse as the main beneficiary.

Husband made failed PETS worth around £220,000.00.

The total estate of the husband excluding the PETS is approximately £250,000.00.

My question is whether or not the estate can be treated as an excepted estate.

Reading the rules, they state that if the estate is less then £3,000,000.00 and the estate passes to a qualifying spouse or civil partner, the estate can be treated as an excepted estate.

My question is, does the fact that the residue is treated as spouse exempt although it is passing into a trust mean that it can qualify as an excepted estate.

In the event that the Trustees decide to appoint all of the assets out of the trust to the surviving spouse, could we then proceed without an IHT400 and would the appointment out need to be dealt with before we apply for probate?

Any thoughts gratefully received.