Not the icons mate.
But yes, merging games is impossible. Perhaps you could get away with much faster production time editing and retexturing some tank models, at the same time re-mastering the old maps from existing CoH3 environmental assets rather than rebuilding precise building/terrain details as they were in CoH2 maps.
Right now, the content is a joke, and if there is a choice between two remastered CoH2 units/maps, versus one new CoH3 asset from scratch: I take the first option until CoH3 reaches half the content of CoH2.
Reuse audio, icons, base-models, gameplay role/design of the Sturmtiger. Bring it to the CoH3. It would have been fine if Relic weren't laggards with launch content, but we are at the position where the team is scounting for the 4vs4 map, maybe summer you will get some actual game DLC, yet the quality of it might be botched anyway.
We are almost three months in, there is 0 new content. Skins or some bug-fixes aren't content.
Merge both game into [COH World] then sell content patch etc. For me its already the same game, just not compatible yet and not as good as the previous one. We cannot afford to split the player base. @relic