How to copy part of a text, iOS10
Best way is to select "forward" then you can select part of the message to copy. Apple should fix this though.
In iOS 10, you can only copy an entire message. You may then edit it upon pasting.
When the Tapback options show up after long-pressing a message, you get the option to Copy at the bottom of the screen.
Tapping More… lets you select multiple messages to Delete or Forward.
No, it's not possible with a non-jailbroken iOS 10. You can select the entire message to copy first and then after you paste you can edit the text.
Easiest solution I found was to copy the entire bubble, then paste it into the text area to send, and in that area you can select just the single word or portion you want like normal text. Once selected and copied, just delete the message and don't send it.