The first few years after formal diplomatic talks between Dunians and Heizar were always going to be tense. Initially the Dunians moved out of old Monument, and a large area between the two cities was formed as a no-go Zone for temporary diplomatic security. The majority of Dunians stayed in this city, though some emigrated to the Commune - a new settlement formed against the rising prevalence of laws in Monument, and based in an abandoned Heizar city to the North past the mountains.
This division of culture, both internal to Dunians and between them and the Heizar did not fully halt the integration of Heizar into the city. While initially there were only embassies, it didn't take long for the first Heizar to move into the city and integrate into the population. The city became a beacon of progress and the unity between the two cultures' technologies brought the development of the Monument to the forefront of scientific advancement. The remnants of the ship also allowed for sprawling underground complexes, allowing for an extremely interconnected city.
Eventually, the gap between Old and New monument shrunk. The Heizar from the south-east island who had reclaimed Old Monument slowly softened their views on the Dunians, largely due to the proximity of the Dunian settlement. While some resentment still existed in the older generations, on the 50th anniversary of the crash, the two cities officially became one again, under the name Monument.
It seems Dunians were never destined to live in one place forever, however, and it didn't take long for many other settlements to begin forming further afield. Initially these were mostly Dunian-populated settlements on the various continents of the planet, but small Dunian areas sprung up in many Major Heizar cities.
Of course there were some for whom even the same planet was never the final resting place. Within 5 years of being constructed, the 10 rockets that had been constructed on the outskirts of Monument went off into the depths of space, populated by 1000 applicants, including some Heizar, bound for the great unknown. Shortly after takeoff, one rocket, believed to be carrying the leader of the expedition, separated from the others. The fate of all 10 ships is still unknown.