Visa Journey reported average for I-130s at the Vermont Service center is 422 days. You could be looking at early next year before the I-130 is approved.
1. Yes. You are still obligated under the I-864s until they become citizens, gain 40 quarters of work credit, leave the US and lose their status, or they die.
2. Your income sounds sufficient, but check the I-864P for total household size..