Chiaki is sort of a blank slate for now (not much parts in the story besides the current end) so you can change anything about her. The situation in the end concerning Chiaka could change in intensity (a child vs someone of the same age) but if that doesn't impact the final path of the story then it's all good.
In terms of lewding, I feel like people who already branded Chiaki as a child would have a hard time adjusting to it but for those who don't, more routes are always welcome. Just depends on how her route would go (no for co-dependency).
Extra note: the patreon link leads me to the subscribestar as well.