So, as someone who's up to date on Twilight Axis, here's some information I can share with you.

So far, no direct links to Unicorn- but a very strong link to CCA.
Basic story is this: Ex-Zeon engineers living new lives are forced via blackmail to assist a Federation (?) squad of Special Forces to investigate the remains of Axis and recover the Sazabi.
*Upon entering, the team are attacked by a team of new Jegan models and the Gundam Tristan.
*Our protaganists escape into an underground hangar and find a Zaku lll that was customized, but never used for Char's use by his wife.
*Using the Zaku lll, they manage to drive off the Tristan. Later, the team go deeper into Axis. A new, space combat Byarlant is discovered, and the protags jump into an R-Jarja (!) to fight it off.

There is a direct link to Unicorn. Character asks another what he knows of the Laplace incident and then mentions the Unicorn Gundam.

The Ronah family make an appearance discussing the contruction of the Frontier colony. Twilight Axis is a prequel to F91

Good things with IBO
1.Main protagonist is actually an antagonist. In enemies and some viewers pov.
2.Main protagonist is not a wuss crybabies as portrayed in many Gundam series. Furthermore he is more heartless and dont hesitant to kill
3.No superpower human. No Newtype bullshit. Main problem in many Gundam anime. But then Alaya Shiki is more to superpower human too?
4.No beam spam. It is an ancient weapon and they more to melee wielding.
5.Friendship/alliance bonded. Although there is a slight betrayal but it didnt happened. I like the idea McGilis and Tekkadan joined as one force.

Bad things with IBO
1.You think we dont get a crybaby but again there is a man named Iok Kujan.
2.Waste potential of good plot. McGilis didnt plan properly to face Rustal. Bael is not at its limit. Would be nice to see what's so special with a mobile suit with a human soul inside system
3.Forced death. Man, Mari Okada.. You are not a Tomino. Even your Ano Hana anime I didnt shed a tear.