I think the heart being there is just them not taking it out of the level because “who cares”. Like that could be a heart for anyone at this point in time.
I think the really only solid evidence to the “timing” is actually the first level. It seems more than obvious that only a bit of time has passed since Jordan Cross’ death. Since much (but not all) of the recording stuff is still there, and the staff is only now just cleaning up after the party. It would seem to me that they were forced to leave the whole wing untouched until the investigation was completed which could have been a few days to upwards of a month. Its hard to pinpoint an exact date, but it does seem to tie into Jordan’s death. Unlike the heart that is really just there (I have not seen anything about saying it was for an upcoming patient named Sodders, or for a now deceased patient named Sodders. To me that just sounds like they didnt want to bother with taking the heart out or could have been like "its someone elses new heart. Where as in the Bangkok one they make a point to have crew cleaning up after the party and people still working in the sound studio but big names no longer there. I will have to go back and play this level again and hang around that area to see if they talk about Jordan at all to see if they give a more concrete timeframe to work with.
But to me this indicates to me that most likely the entire Patient Zero campaign takes place between Bangkok and Hawke’s Bay. If we assume that Jordan Cross’ funeral was a week after his death, and ICA didn’t suspect a shadow client until after Thomas Cross’ death, then they would have needed time to try and find the client there was enough time to slot it into that window. Even if it took them up to the ending cinematic with Diana and Constant in 2016. I could see the conversation she has with 47 at the end of the Patient Zero final cutscene being only a few minutes before she meets the constant.
But despite all the longwinded unneeded response, I don’t think it really matters. Or I should say that its actually Canon. I know its treated like it is or it feels like it is, but timing with canon story events and the reuse of location and similar assets mean its unavoidable that there should be some mention of it. But I don’t recall any. I need to play it again but I don’t think that they really make any mention to Militia in any knowing capcity in The Vector, which either means this takes place before Colorado, and 47 just happens to be there, or it takes place a few days later and they couldn’t care less about the events of Freedom Fighters to even mention a simple “you’ve dealt with this Militia before” or something. It would also be normal for any small Army like that to move camp once one location became compromised, so unless The Vector and Freedom Fighters happened in the same week, one of the stories just can’t be canon. I doubt anyone would argue that the main game isnt canon.