It is possible to embed posts from public channels in web pages. In fact, if your group is public, you can even embed conversations in your web page. Try the announcement link here https://t.me/telegram/83
Wire (wire.com) is now fully open sourced. You can build your own client from https://github.com/wireapp and use it to talk to other user using the official clients.
I've noticed that a new device added to the account will not see the history. It only sees those messages that are received or sent after it has been added to the account.
You will find https:///www.wire.com/ interesting. e2e encrypted, clients for Windows, Mac, Android & iOS. And chats are synched between all your clients. Also .. no phone number required to sign up; use your email.
Why aren't you using Wire (https://www.wire.com)? It is cross platform, end to end secure w/ open source audited crypto, focuses on app usability, and doesn't need a phone number to sign up.
Users can always revoke their public keys. The same public key does not have to be used continually. Allow users to revoke their keys as often as they like. Heck, force the keys to expire in 1 day if you like! We already expect the sender to be online. The sender can check for key revocation before they send the message. Or let the server send back a error response if the sender used an expired or revoked key to encrypt the message.
Rs 98 / month is for 2 GB of EDGE data per month. That is the normal charge in India for every mobile customer. This is not a special tariff for this tablet.