1, invention requires invention priority, and utility model requires utility model priority. This is absolutely possible.
2. Two late applications may also need the same earlier application as the priority basis. However, you should consider not authorizing another earlier application, otherwise it will bring trouble to the application of the day.
Of course, it's best to make sure that neither application is public. Because the disclosure of the earlier application may reduce the novelty and creativity of your newly improved technical scheme in the later application.