Will I be able to have basic conversations with this course if everything is level 5?
Obviously I will be able to talk, but to what extent? I'm just making sure before starting to learn, as I wasted time on the arabic course.
Hindi? Probably not. It's not a huge course here, but Hindi is more complex than many languages and that doesn't seem to be reflected in the number of lessons available.
I spent a lot of time learning Hindi some years ago, and although I was able to manage some short exchanges in India, which was useful and very satisfying to be able to do it, a full conversation wasn't an option.
And although I've only looked very briefly at the Duolingo Hindi course, intending to use it to revise/refresh what I already know and what I've now forgotten, it looks to me as though the course here doesn't go even halfway to what I learned previously.
On Duolingo, I'd say that French, Spanish, Norwegian, Russian and maybe a few others take you to the level where a very basic conversation may be possible, but even those really need additional vocabulary and more practice listening and understanding.
Duolingo, on its best courses, gives you a good, solid, firm basis of a language - possibly better than you'll get anywhere else. But you really need quite a lot more if you want to go to the country and expect to be able to speak the language with native speakers.
Having said all that, I doubt whether learning Hindi here would be a "waste of time". As I said, the structure of language learning on Duolingo gives you a solid, basic understanding that you won't forget quickly - if you do the courses properly. It's perfect for building your skills towards fluency with other resources afterwards.
I think you will be able to ask the way, for things in the shop, tell who you are, etc. Since Duolingo is a lot of tapping/multiple choice, it depends on whether you can recall when you are in a certain situation. The final level is half way Elementary (level 2 of 6). You will be able express past and future, but not subtle things with compound verbs so much