hello! I am a glassblower and lampworker that specializes in replicating historical glasses particularly venetian stemware from 1800s-1900s.
I cannot date these or tell you were they are from but I can tell you that these were not made at the furnace(except for the last picture which is possibly furnace worked) but were instead lampworked.
my proof is in the definition of the rigadin, or optic molding and in the proportions of avolios and knops. also the shape of the flower petals is more similar to that of a lampworker than traditional furnace work (petals look too thin and even colored, no chill marks).
the first three pictures assure me the piece is lampworked by the lack of a top disc on the upper avolio aswell as the definition of the optics
the first picture on your second post the blue flair that was made by pinching with tweezers goes down all the way to the white spiral which indicates additional heating associated with lampworking. also the avolio on the cup doesnt have a top disc which is also associated with lampworking.
the optics and handle on the third picture of your second post immediatly assures me this piece is lampworked. if you look closely you should find the ridges on this piece are more pronounced on the inside of the vessel than on the outside. had this been made at the furnace the ridges would be on the outside due to the use of an optic mold, however the ridges on the inside show that scallopped tubing was used. also the stub connecting the lower portion of the handle would never had been done at the furnace and was done as the lampworker couldnt properly control his heat base to add the handle.
the fourth of the second is lampworked because there are no tweezer marks on the handles and the stem is too thin and too wide, this would rarely happen in furnace glass.
the fifth of the second may be furnace worked due to the shape of the avolios, however the downturn the lip of the foot takes makes me sceptical. a furnace worker would have difficulty in doing this and one with the skill to do so would have much cleaner optics.
this doesnt mean they are not blown glass or are not italian just that these were not made at a furnace.
for more clarity, look up cesare toffolo on youtube to see these techniques demonstrated. and to see a true muranese furnace worker look up davide fuin, or lino tagliapietra.