I have written a family tree for Harry Potter but don't know where Honoria Dumbledore and Araminta Meliflua Black go - any suggestions?
Honoria is an aunt of Albus, Aberforth, and Ariana Dumbledore. It's unknown whether she's an aunt on their mother's side or their father's. From HP Lexicon:
Honoria was the aunt of Albus Dumbledore. He referred to her as his “maiden aunt.” [...] It is unknown whether Honoria is Kendra's sister or Percival's. Even though Kendra is a Muggle-born, there is precedent for Muggle-born siblings both having magic (like the Creeveys).
See also this talk page for more speculation and evidence supporting her being Percival's sister, but nothing really certain. There's also a Harry Potter Family Trees Wikia (because of course there is) with this page listing the known Dumbledores, but again no info about which side of the family is Honoria's.
Araminta Meliflua Black
Again we don't know her exact position in the family tree, only that she was a cousin of Sirius and Regulus's mother. From HP Lexicon:
Appears on the Black Family Tree; cousin of Walburga Black.
However, in this case we have a little more information because JK Rowling has actually drawn a canonical Black Family Tree. I found it from this question; image reproduced here:
So we can speculate that Araminta Melliflua might be the daughter of Callidora and Harfang Longbottom, or of Charis and Caspar Crouch (either of which would put her in the same generation as Walpurga, as a second cousin). But again, this is speculation and we don't know for certain.