I can't see the Cubs trading Bellinger before they have some other deal in place. They could be gauging interest for future moves.
Honestly, Seiya in RF and a better bat with more power at DH that likely comes cheaper than Bellinger is a possible move. Money saved could be spent elsewhere, like pitching/catching. Soto is also a move but that's far-fetched until we see the Cubs meeting with him at least.
It wouldn't be that hard to trade for a bad-fielding MLB hitter who can DH and hit better than Belli. They'd be trading Belli's defense in RF and position versatility for more thump, and we already have several guys in the lineup that are glove-first players (PCA/Nico/Dansby) & no elite hitters so that may make sense. Less likely they go 3-4+ years on a FA given all our hitting prospects.
The risk is losing the depth Bellinger brings for PCA/Busch at CF and 1B in case of injury. For CF depth we still have 3 young OF prospects in Iowa on the 40-man (Alcantara and possibly Canario can play CF), plus Tauchman who is passable in CF (good hands/instincts, very average speed/range). Mervis, Ballesteros, and whomever is our corner INF bench guy could cover 1B if Busch is injured, though they're all a likely downgrade from Bellinger.