QUESTION: I need to include multiple lines of on-line chat dialogue in my story. My question is about rendering the punctuation of it.
For example, in a rapid fire online chat exchange with short snappy one word answers, in real life, the writers would be unlikely to use much punctuation including periods. Can I eliminate them in my rendition of it to the page?
As long as what you write is clear to the reader, I see no problem with doing the punctuation or lack of it as you wish. Just be consistent.
One thing to consider is who your reader is. If your book is aimed at younger readers, they will be much more comfortable with nonstandard punctuation than the older reader.
To differentiate the chat dialogue from the regular text, I suggest you narrow the margin on both sides of the page by another inch and use names in the same way as in movie and play scripts.
JANET: OMG OMG Dirk asked me to the prom.
MARY: WTF He asked me, too!
Emoji images are something you should avoid. Some are copyrighted to be used for pleasure and individual sharing, and a for-profit use in a book would be illegal. Also, the inserted code may very well not be translated so your reader will be left with code gibberish instead of images.
NOTE: This advice should work for any of the many new ways to communicate with smart phones, etc.