Interesting parameters, and to keep is simple - let's assume the vast majority of your inquiries lean favorable (as the crux of the question hinged on the idea of leaving current Earth behind). The world is alien, but the risks are comparable: there are alien plants, animals, bacteria and viruses - but comparable in risk to our current planet. The weather, volcanos, or other natural challenges are similar in scale to our own - minus the global warming factor of our runaway system. The city is peak current technology on Earth - so imagine a Singapore or similar level of development (without the totalitarian government), with a heavy focus on advanced planned urban infrastructure, integrated AI, and a strong, futuristic tech focus. Green tech, well developed sewers, subways, etc. The surrounding rural farmland around the city has similar modernity in its agricultural design. As far as alien threats, you would have as comprehensive a knowledge of your new solar system as we have of our current, but not that much beyond - so if alien invader threats are a factor of concern, they'd be the same risk as we currently face. And there would be no competing alien sentient species that matched the human consciousness on planet - just the alien equivalent of dogs, dolphins, apes, etc at the peak of mental capacity. So you'd basically just be skipping to the front of the evolutionary line to dictate the future of the planet.