That's an interesting application of Isaiah 26:19, but the speaker who refers to "my dead body" is not God which is obvious from the context, but the choir which verse 1 refers to.
In Barnes Notes he says "it is not the language of the prophet Isaiah, as if he referred to his
own body when it should be dead, but it is the language of the choir
that sings and speaks in the name of the Jewish people. 'That people' is
thus introduced as saying 'my' dead, that is, 'our' dead, shall rise", i.e. they will be restored to their privileges and land.
How could "my dead body" (nblthi) refer to a collective dead? Well, it does as can be seen in Leviticus 11:11 ("...you are to loathe their dead body [nblthm]"), Psalms 79:2 ("They have given the dead body [nblth] of your servants..."), Isaiah 5:25 ("... and their dead bodies [literally "their dead body", nblthm] will become like the offal..."), Jeremiah 7:33 ("And the dead bodies [literally "dead body", nblth] of this people must become food...").
Likewise, Keil and Delitzsch Biblical Commentary on the Old Testament
says of this expression, "my corpses will rise again" (יקמוּן נבלתי,
nebēlah: a word without a plural, but frequently used in a plural
sense).
This understanding is clear in both the LXX ("those in the memorial tombs") and Vulgate ("my killed ones") translations of this verse. Barnes suggests that this is a parallelism (common in the Hebrew Bible) with "my dead" [nblthi] in parallel with "your dead ones" [mthik] and refers to the remnant who were civilly dead but will be restored to their homeland, in contrast with the tyrants of Babylon in verse 14 who will not rise up again.