Tyranids imminent!

A small planet spewed into an area of space in the eastern fringe. How and why this occurred is not known. The Imperium was quick to blame the forces of Chaos.
Fearing what foul daemons and creatures may be on the planet, codenamed Planet Vegeta, the Imperium observed it for many years. Vegeta is fertile world but storms are suspiciously common. No life could be detected.
However, no one was game to venture there. Many planets are abandoned on the eastern fringe that the Imperium could take control of again should they wish to; and so controlling Vegeta was not necessary.

The planet Vegeta was effectively forgotten. Until one day...

A Long Range radar blipped life on planet Vegeta. Orks.
The Imperium observed, still fearful of the planet. The Orks battle among themselves, as is natural for them.
Company Master Baradiel, Master of the Dark Angels Third Company, a man who passionately hates the Orks after recently suffering a humiliating defeat to them, recklessly decided to invade to seek personal revenge. He tried to persuade the powers that be he should attack now before the orks become united under a single warlord. Much easier to take them apart one warband at a time.
He was declined.
He invaded anyway.

He set up base in an area unhabitted. To his surprise, ruined settlements were everywhere. What planet was this initially? It could have been one of an untold many.
Whilst discussing plans, a support staff psyker announced he felt a disturbance in the warp. A kind of nothingness. Baradiel dismissed this.
A day later communications went down. Baradiel halted any further movements of his force. He could not continue until his communications were back.
Embassies from Eldar and Tau forces suddenly appeared at Baradiels camp. Their news was not good.
Tyranids imminent!
Baradiel declared they all must abandon the planet to its fate. Leave the Tyranids and Orks to kill each other. The Eldar & Tau said this would not be wise. For those races thrive on war, and the Tyranids and the Orks will only grow stronger and the ultimate victor will be more powerful than we could ever hope to stop. We cannot allow the Tyranids and the Orks to fight! The Tau chimed in "It's for the greater good." Baradiel told him he was a twat and should shut up.
At first Baradiel was adament to forsake the planet, but with a little cajoling (and a few Eldar maidens in his bed) Baradiel agreed to help prevent the Xenos races from fighting.

Before an effective plan could be made, warnings sounded. Tyranid swarms from the East. Orks from the west. The Dark Angels, Eldar and Tau are stuck in the middle. Baradiel took command. He and the Dark Angels will concentrate against the Orks, The Eldar the Tyranids, the Tau to provide fire support all around.

Castle up and Defend!
Dark Angels, Eldar and Tau vs Tyranids and Orks.
Note that I know this seems one sided, but with variable numbers of members, I intend for us to reach an agreeable points value by increasing the points value of an army or having 2 Tyranid armies for example.
Each army to comply with the normal FOC.

Planetstrike Rules and terrain except the following alterations: The Tyranid drop zone is to the East, and the Orks drop zone is to the West. This is mission 1) Planetfall in the planetstrike book.