There is one verse from Revelation which may have implications for this discussion.
“And he shewed me a pure river of water of life, clear as crystal, proceeding (ἐκπορευόμενον) out of the throne of God and of the Lamb.”
Now it is worth noting a few things. First, the verb used is the same as in the Creed. Second, is the way St. John speaks of the Divine Persons. God refers to the Father, as is the usual case for the New Testament, the Lamb is Christ the Son, and the River of Water of Life refers to the Holy Spirit as in John’s Gospel (cf. Jn 7:38-39). John speaks of one river proceeds from one source, the throne of God and of the Lamb. This seems to reflect the definition of Florence that the Spirit proceeds from the Father and the Son as from one principle through one spiration. I would be hesitant to say that this definitively proves the Latin doctrine, but I would hope this would give Orthodox polemicists pause before insisting that St. John affirms that the Holy Spirit proceeds from the Father alone when the verse from his Gospel does not use the word alone and he speaks of procession of the Holy Spirit in reference to the Father and the Son in his Apocalypse.
I’ll refrain from commenting on the other Orthodox objections. I don’t want to misrepresent the Orthodox views, which I’m not sure that I fully understand.