Re: How does Aikido compare to Aiki-Jujutsu?
Hosaku Matsuda, who is often cited along with Takeda as having taught Daito-ryu to Okuyama, by numerous accounts also was awarded kyoju-dairi by Takeda. So, even though he's not a relative household name in these discussion circles compared to others who were awarded the same certificate or menkyo-kaiden, that doesn't automatically mean he wasn't at least adequately, if not comparably skilled.
As for the Daito-ryu Hiden Mokuroku influencing the kihon waza, it also seems to be the foundation for the various Aikido styles (Aikikai, Tomiki, Yoshinkan, etc.) regardless of when in the 20th century they were founded -- and Morihei Ueshiba was considered no slouch regarding aiki.
A safe bet is that Okuyama's "aiki" was similar to that of mainline Daito-ryu (a position Andrew Bryant supports) vs., for example, what you experienced from Howard Popkin. Even if that's the case, then the difference, again, lies in the nexus between the jujutsu and shiatsu -- so yes, a "different flavor of body skills", but that's what Hakkoryu has maintained all along.