Okay...this can be tricky...
The colors in photos can make it tough to determine if it is vintage or Post 86. In real life, I can spot and determine vintage a mile away.
The covered casserole is definitely vintage. I think the color is light green.
Under the covered casserole, there are plates. I'm not sure if they are vintage light green or Post 86 in a color they call Sea Foam. FWIW, I think the plate just under the covered casserole is vintage. You can measure the old plates to also determine if they are Post 86 or vintage.
measurements are as follows light green casserole 8 in., light green and yellow plates 9 1/2 in., light green round platter plate 14 3/8 in., 11 in. round yellow serving dish with 1 inch rim and standing 1 9/16 in. high (see photo below), 3 small plates 6 1/4 in. (2 styles see photo below), all have kiln furniture marks, the darker green bowl is 7 in. to the outside rim, the red bowl is 9 1/2 in., and I also have an oval platter that is 9 7/8 X 12 5/8 in.
The cream soup bowls...are those marked on the bottom? They appear to be yellow, and vintage. Those bowls can be super hard to find. I think they were made until 1959 or so. yes they are yellow and marked on the bottom (see photo below)
The third photo down shows what I believe to be a vintage one quart veggie bowl in Radioactive Red.
phot of bottom below There appears to be a vintage bowl in MEDIUM GREEN, which is one of the hardest colors to find, and used to bring a HUGE premium. That green bowl could also be Post 86 in Shamrock...it looks like a new cereal bowl. What mark does the bottom have? see photo below for the mark
Also in the third photo, there are saucers for tea cups. Appears to be yellow and ivory in colors. Feel blessed if you can get $2 each for them. there are 2 tea cup saucers and one without an impression for a teacup, all are the same yellow color, see below
The fourth photo...you got me on that one. Is that the bottom of a new tea pot or carafe in Turquoise? that is the bottom of the covered casserole, it is a light green color
The fifth photo...that mark is a dead ringer for vintage.
that is the bottom of a light green plate
The sixth photo...also a dead ringer for vintage. Do you see the three firing pin marks? The three firing pin marks are a sure and definite way to help date vintage Fiesta. Vintage Fiesta was fired in the kiln sitting on a wire stand that poked holes in the glaze.
all the plates have these marks
The seventh photo...definitely vintage. Is that the bottom of the Radioactive Red one quart bowl?
yes it is
The eighth photo shows a vintage Fiesta plate of some sort, even though it isn't marked. Not all vintage Fiesta is marked. See the firing pin marks on the bottom of the plate?
that is the bottom of one of the teacup saucers
Does this help??