The Satsuma now appears dead too.
So it appears that a small sized Satsuma on dwarf rootstock, covered by a clear vinyl plastic enclosure, was not able to survive.
An Arctic Frost growing on its own roots, not protected, in a kind of shady spot, which was moved outside a little too early in early March with very cool but not freezing temperatures, died back and then recovered, was not able to survive either.
But this was definitely a colder Winter than usual. Snow 16-18 inches deep (which is unusual here) and temperatures in the yard that I estimate went down to about 14 F.
It is in zone 8a, but in the Pacific Northwest where temperatures do not really begin consistently rising until very late April.
The Arctric Frost might have done better if it had been grafted onto trifoliate and if it had not been growing inside and suddenly transferred into the cold outside in March, which resulted in a fair amount of die-back due to the sudden transition, which may have put it in a position not to be able to handle the following Winter as well. Perhaps planting it in a warmer sunnier spot might also have helped.
For comparison, the Yuzu on dwarf rootstock (probably the same rootstock variety because same nursery) survived, still has retained a few of its leaves, although it looks like it has gone through an ordeal and there is just a little bit of branch die-back at the extremities.
What I think this proves is that an Arctic Frost is not going to easily survive a cold winter in the Pacific Northwest region.
This is of course a very different situation from Texas and the South.