Bug Test my 4 apps and fix those

Hi Hope you are well I currently own a business in UAE, which has an app "Sober Driver In UAE" (you can find it on both IOS and Android), + "Sober Employee In UAE" (also android and ios). My business offers designated driver services (basically my drivers drive your car, when you are drunk and dont want to drive it). My app operates on a similar model as Uber (but obviously we provide driver and not the car with driver). There are multiple things that I want to modify on my app, and I would like you guys to look into it and let me know what you think and what will be your cost on fixing certain issues and adding new ones, please find the list below. Regarding the App Coding, I will get the codes hopefully next week, I'm well aware of the fact that you need codes to estimate value, but it would still be great if you could look into it now and give me estimated cost and time frame. fyi, the four apps costed me 6k USD. 1. Bug testing (main thing) 2. Implement the OTP on sign up (I can actually ask old developer to do it, if this will affect price hugely) 3. Add 2nd and 3rd drop off feature. So customers can select multiple drop offs and there will be additional price on that 4. Implement pop-up notification reminder on certain days, example: "sober driver wishes u a great weekend, book your driver up ahead" 5. Apply identical app but to different cities (so just upload map of a different city and apply different currency). This shouldn't be difficult, cause I've got admin panel, where I can edit price and add or delete cities, but there might be more to it than that, thats why I'm mentioning here 6. Add a space where we can advertise our partners. On the top of the screen I want to have a scrolling ad of our partners (image +text) and if customer clicks on it, they should get redirected to partner website. 7. Recommendation to a friend - I want you to implement this feature where customer can send a download link to his friend via whatsapp, and if a new friend registers and books a ride and completes it, then friend that recommended it gets 10aed off on his next ride. I will give you the list of other things later, for now please check out the app and let me know of the price. There are many more features that I want to add on it, but I want to first see how you deal with these. And let me know how many apps you developed in the past and were they similar to this.