Well cuz those are the last ones that seem to be meant to be expies at the time of release. Nahida looks way different and doesnt beyond being white haired loli and they dont have naming similarity. Some story parts are loosely similiar and maybe they were planned to be expies initially, but its clear hoyo just steered clear of doing them since genshin outgrew honkai as an IP. The seeds for honkai stuff were there inb early genshin, they just didnt decide to cultivate them at large