Why aren't Apple.SE and Android.SE present on the migration list?
Why should they be? The two sites have nothing to do with software development on Android or iOS or Mac OSX. From Apple.SE's (Ask Different) FAQ:
Please refrain from asking about ...
- Apple Developer Programs or iTunes Connect (including iAd and the
iBookstore)
- programming, with the exception of AppleScript and Automator
And from Android.SE:
Please note the following topics are expressly off-topic here:
- Developing/programming for Android (please ask these questions on
Stack Overflow)
So basically, these two sites are about the products and hardware, not the development.
Why are Sharepoint.SE and TeX.SE on the migration list?
Well, they do have to do with programming a little bit (Sharepoint more than TeX). Not really though. The main reason is that because they have to do with programming, new users do ask TeX and Sharepoint questions on Stack Overflow that would probably do better on those sites. We may not have seen them, but I'm sure there were a few... If I'm wrong, please comment.
And what happened to Server Fault?
Same thing that happened to Programmers.SE! Too many bad questions were being migrated from Stack Overflow to the site so instead of letting that continue to happen, they removed the site from the list. See here: Regarding the high number of rejected migrations from Stack Overflow to Server Fault
TL;DR: Look at Servy's comment:
The list isn't based on what sites are likely targets based on the tags you're active in, they're based on the number of migrations made across all of SO, and for that these are the sites most commonly migrated to (with some special casing around serverfault).