There were other DLC bugs reported too.
Assuming you are playing the USA/EUR version, I'd just make sure:
1) The localized title of that is Hm? Ah, Yes. So you need to sort by name and select the option for H to see it.
2) The localized title of that is The World is Mine. So you need to sort by name and select the option for T to see it.
I'd also make sure you have hard difficulty selected.
That's pretty bad because everybody knows when indexing anything, you cut off the words "the" and "a" and put them at the end.
BTW, Miku's Supreme outfit (your avatar) is in DLC #1 and it's super-cute.