ArangoDB pedigree graph traversal - graph

Question

I have an example pedgree with a structure as shown here.
My ultimate goal is to extract the ancestry of certain people in the so-called trio format, which is a table with columns id mom dad.
In my example, the result for the pedigree of the two most recent persons G and H would be
+-----+-----+-----+
| id | mom | dad |
+-----+-----+-----+
| D | A | B |
| E | C | B |
| G | D | E |
| H | F | E |
+-----+-----+-----+
The closest thing I could come up with in AQL is the following query.
LET last_generation = ['people/G', 'people/H']
FOR person IN last_generation
FOR v, e, p in 1..10 OUTBOUND person is_mom, is_dad
LET role = contains('mom', e._id) ? 'mom': 'dad'
SORT e._from DESC
RETURN DISTINCT {'id': DOCUMENT('people', e._from)._key,
'parent': DOCUMENT('people', e._to)._key,
'role': role}
Altough the result is not yet in the right format, post-processing is easy.
Now my questions are:
I am forced to use the DISTINCT keyword to ensure uniqueness of rows. However, I would like to avoid unnesseary traversal in the first place rather than filtering. Ideally, I think I need the option uniqueEdges: "global", which is sadly not availabe any more. For instance, after having processed the pedigree of person G, I don't want to traverse the part of the pedigree shared between G and H (i.e., person E and its parents) again. Using uniqueVertices: "global" is not an option, because I would then miss the edge between H --> E.
Is there some kind of option to know the edge collection type during a traversal rather than using the kind of cumbersome checking I do? Please note that it is not an option for me to put the sex into a property of the person (which is reasonable for most humans), because in reality I am dealing with plants, which can (usually) be mother and father at the same time.