There's no real way to know, and it's tough to make assumptions based on Savage SCoB, because it was in a very different position from Savage Alexander.

Savage SCoB was not part of progression in any way, had no unique drops, no higher item level gear than was already available elsewhere, etc.

Savage Alex may be part of general progression (depending on the item level of Alex 2), has unique drops, and has higher item level gear than is (currently) available elsewhere.

Personally, I would be surprised if they changed any mechanics in Alex Savage, and don't anticipate that they'll put echo in, though that wouldn't surprised me. Most likely Void Ark will be i200, Alex 2 i220, new tomes i230, Alex 2 Savage i240, so that Alex Savage can be skipped over once it's not current.