Matthew 16:19 ἔσται - eimi - I am, exist
Interesting that you highlighted the wrong word in your list. We are not looking at λελυμένον which is translated loosed. We are looking at when it was loosed. Not in any Greek lexicon can the Greek word ἔσται - eimi be made to mean "will be".
I know the Catholic way is to divert the attention but let's keep on subject.
ἔσται verb 3rd sg fut ind midVerbs have inflections. This one is future tense, professor.