Answering your question widely depends on what you are going to do with your app, however, I would give you some advice:
1- Using another library to manipulate the DOM in a Framework just like Anuglar2 or Ember is not required because you can do that with the framework APIs itself in most of the case, although in Anguar1 we had jqLite but in Angular 2 there is no need to use even that. So, think what you wanna do with jQuery and then go and search within Angular document to find the proper way wit ng2 itself.
2- Using a UI framework is not really hard but it again depends on what you have planned to do. For instance, I love Material Design style and for a lot of good reasons especially when it comes to select a framework for Mobile, I would go for MD, in particular , Angular Material. So, if you have any clue what you are going to do with your app in the future but you wanna at least stick with the Angular team and their ideas, the best is to work with Angular Material.
3- There are lots of other frameworks that you can try such as Foundation, Ink or in Mobile development Ionic and much more but all in all , it depends what you wanna do.
4- If you are new to Material Design and you are mostly going to rely on Desktop version and responsiveness so Bootstrap, especially version 4 is an awesome choice.
5- in my perspective, it's always the best to stick with Latest version. Although Angular Material is not finalized version yet, I would strongly recommend using their latest version by the time I am writing is v2.0.0-alpha.9-3. The team already mentioned that this version is usable and it's pretty near to final version.