Bobbie's send-off was postponed due to the Writers' Strike. Monica's send-off was postponed due to Chad Duell's departure. The producers wanted to be sure that the recast of Michael was in place and "working out" before they wrote Monica's death story, given the issues they'd had with re-re-recasting Molly in the midst of the surrogate story.
I tend to over-think these things, but I think I've figured out what Michael is up to with respect to his recent behavior toward Chase, Dante, Brook Lynn, and Lulu. Michael is insisting to everyone that Willow is much more unstable than they realize and adopts this colder attitude that they have not seen before. When he insisted to BL that he was going to make sure Willow was never around the kids again, he knew that would get back to Chase (her husband). When he said the same to Lulu (and she overheard him saying it again), he knew it would get back to Dante. Michael knows that if he can manipulate Chase into going totally overboard with his defense of Willow, Chase will look like a biased/unfair player in the investigation. Anything Chase finds that implicates Michael will be questioned, maybe even thrown out of a case formed against Michael due to Chase's perceived bias. If Chase gets much more "pro-Willow," it might undermine his marriage, as well. In the situation with Dante, Michael knows Dante isn't as easily manipulated, but he will most certainly call out his partner Chase if he sees Chase going so far off the deep end. Dante's constant effort to make himself seem "above reproach" with respect to his family (futile as it may be) would compel him to join in the chorus accusing Chase of having lost his objectivity. Chase's decision to investigate "on his own time" will end up getting him suspended, maybe even fired, and Michael manages to keep his hands clean in the whole thing.
This effort pf Michael's to drive Chase to ruin his own career and possibly his marriage in the name of saving "poor victim Willow" totally mirrors the situation with Nelle years prior, where she killed her boyfriend and convinced the investigating officer (Chase) that she was innocent. In his crusade to save Nelle from prison, he lost his job and helped a murderer go free. Here is Nelle's twin sister accused of trying to kill her own boyfriend and Chase is falling into the same behavior. Even if Willow is really innocent, he ought to be able to spot his repetitive behavior---did he learn nothing from the Nelle situation? Also, this effort Michael is making to discredit Chase and to make him appear "compromised" is the exact same thing Sonny has been doing to the ADA Justine Turner. His effort to "charm" her and have her over for dinner, etc. will make her less able to prosecute him since there will be an appearance of impropriety.