>>23528200
They care enough to make the Dominion. The Archangel itself is relatively disposable given they already have all the data.
>>23528702
The computers there had the data for the others. That's how the Buster Dagger was made. It's arguable that though the making and testing all happened at Heliopolis, it wasn't the only place that had the data because the Druggie machines were made too. They could've just had backups or copies of the data sent back to Eerth every now and then before ZAFT found out and Heliopolis go boom.