Apple and Android app

General information for the app: internal communications and push notifications
Kind of development: New app from scratch
Num. of web pages/modules: 1
Description of every page/module: We need an app for internal communication, it need to work on Android and Apple OS. Both functions will be a single page and the design elements should be customisable by us, including the app icon. Design elements are button name, background, logo. We also need to be able to customise the email address information is sent to.
Description of requirements/features: function 1

The app has 3 buttons and only one page.
1 to link to a video file hosted on Vimeo (we need to be able to change the link occasionally)
2 A link to a website
3 A way of sending a message to us that will arrive in email form or to a private website, or other messaging service with text input for name, email address, phone number, website and notes
4 a way to ask a question, similar to above but the email header we receive has the subject Question

We need also to be able to send push text notifications to the app both scheduled and on demand, the app should appear in messenger for push notifications.

function 2

We need the ability to send text push notifications and the users to reply to each notification. there may be multiple notifications at the same time. the reply is a free text input and we receive an email or other message with the reply and a copy of the original notification.
We need to be able to see a list of the notifications on there app and the ability to set an end time for each notification and when the time has elapsed automatically gets removed from the list.

We will of course discuss in more detail with our chosen supplier and need this as soon as possible
Extra notes: