How much would this cost me?

I would like to create a social media site that can host videos like YouTube and have Twitter like features. I'm thinking that I would make it into an app for both iPhone and Android. How much would it cost to make and to host the database? I would like a ballpark figure for total cost.

Disconnect two iphones?

I recently bought an iPhone 8 plus, and I already have an older iPhone 6.
My problem is the two phones are connected, if it rings here it rings there, if I get a message here I get the same message there, and all my contacts were deleted on the older phone but I was able to retrieve them, my problem is how do I disconnect the both of them?

What is the best cellphone provider for this situation?

College student graduating in a year with no job and some money saved. Have iphone, but don't care about model except it has to have LTE other than that i'm fine with any model with it. Only use it for occasional calls and texts, but mostly daily browsing and reading via safari.

What would be the best provider for my situation? At the moment on my parents verizon plan, but not sure if verizon is the best for my situation, any suggestions?

How to recover iphone notes from broken iphone?

So my iphone 6 is broken and i need to recover the notes that i wrote there, as long as i remembered it was connected to my gmail account, How do i recover it? I rarely back up my phone and i really need the notes.

After months of use my phone was blacklisted

A friend of mine purchased a phone from his co-worker, who had purchased it from original owner in his family. My friend has had this phone for over three months working on his plan with at&t and then suddenly the coworkers family member wants the phone returned without a refund and now has blacklisted the phone. Is there anything for my friend to do that would allow him to keep his iPhone with his at&t account considering this is simply put just a bad business deal or is there a way for him to remove the phones IMEI from the blacklist and continue his at&t network?

IPhone X brightness won't go higher than 80 percent?

My IPhone X randomly dims to about 80 percent brightness and sliding the brightness dimmer only adjusts the brightness up to 80percent max, sliding it farther causes no change and sliding it to 90percent or 100percent still looks the same as 80percent. If I wait long enough my screen will randomly get brighter again and go to 100percent on its own. Then later, my phone will randomly dim again to about 80percent again. I checked auto brightness, I checked white point and I even checked low power mode but none of that fixes the issue. I just have to wait until my iPhone decides to randomly fix itself and goes back to full brightness again.