Without getting into details, the existing Sonic Boom storyline doesn't give Lyric much space to fall. Unless you, of course, apply time travel, which technically allows anything.
Surprisingly not so. Sumo Digital has nothing to do with this. Iizuka also confirmed Sonic Team is not developing it. I have zero idea what this could potentially be. Evidently it's a new Sonic game by another external developer. If so I hope you chose more wisely this time Sega. Outsourcing development of a major Sonic game sounds risky after the catastrophe that was Boom.