How much item level we need for the new content?

[aesteval]

Be interesting to see how long before ilvl 360 gear is available through the hunt vendors to help players get up to speed and finish the MSQ before July.

It won't be. The tome gear that gets moved to hunt seals are when the current expansion uncapped tomes are deprecated for current expansion new tomes. The 360 gear will likely switch to Poetics when Shadowbringers launches assuming the devs continue with the decision that Poetics will remain the "old" content tomestone.