So it was pointed out to me today that your line under new grafts:
A single creature can have only 5 New Style grafts. A single creature cannot have more than one type of graft (Construct, Deathless, Dragonic, Plant, or Elemental).
The above does not prevent you from mixing different types outright: You can apply Elemental grafts to someone who all ready has an Aboleth graft, provided you do not have more than 5 Elemental grafts, and do not try to apply a Plant, Dragonic, Construct, or Deathless graft later on.
Appears to be incorrect. In RotD:
An individual can have a total of ﬁ ve grafts on
his body, and all grafts must be of the same kind. A
single body can support only so many growths before it is
overwhelmed with competing biomagical signals, result-
ing in death or, as is more often the case, utter madness.
No portion of the body (head, skin, ﬂ esh, legs, and arms)
can have more than one graft. Furthermore, no character
can have more than one type of graft—for instance, both
a draconic graft and an undead graft (described on page
70 of Libris Mortis or page 214 of Fiend Folio). Rumors of
attempts to bypass these biological limits abound, but
such monstrosities—for that is what such creatures
become—rarely live long
It specifies Undead Grafts as it's example, which is one of the old style grafts. And presuming that Aboleth Grafts don't have some other rules that allow you to use the new style grafts with them which for some reason wouldnt apply to Undead Grafts despite following the same rules, this seems to indicate that old style grafts and new style grafts are incompatible with one another.