Freestyle Fellowship fathered Bone's flow. Everyone should be familiar with their work and Aceyalone's work as a solo artist. They're probably the most underappreciated group in hip-hop history. Examples...
[ame=[MEDIA=youtube]1u533oeOBTE[/MEDIA] Fellowship-Innercity Boundries(Feat.Daddy-O) [ HD ] - YouTube[/ame]
I would say since Myka 9 did most of the actual singing and melodies on there, you can trace a good portion of that style to him (I forgot the other 2 members

). Aceyalone does very little harmonizing, except on that track "Mary" where it's evident at the end of his verse. On his solo albums, he seldom sings at all, mostly raps.
However, being from the West Coast myself, they use a LOT of lazy-tails in the delivery.
In contrast, all the members of BT&H use more vibrato in their vocal parts.
There are regional differences if users were more musically educated, and actively listen for the distinctions.
Even then, BT&H had a ton of legato and really seamless transition with their deliveries and how they "group harmonize" all their melody lines. On the flows part of it, it sounds like their cadences "continually link" at some points in songs.
Both groups styles are nearly polar opposites in approach. I'd say the closest they sound similar, has to be in tempo they choose to pick out to flow over beats. BT&H had an early West Coast influence, but that was more production than anything else.
Soon they evolved and had their own sound.