You can keep the recording for two weeks after it was made, after which point it should be deleted. 
It’s best to make clear that the recording was made under the Read Aloud Licence.  We recommend a statement like this on or near the file:  This recording OR live stream has been supplied under a CLA Licence with specific terms of use.  The content in this recording OR live stream is protected by copyright and, save as may be permitted by law, it may not be further copied, stored, on-copied electronically or otherwise shared, even for internal purposes, without the prior further permission of the Rightsholder. 
Only if CLA get in touch and ask you to log it in one of our normal sample Data Collection Exercises, otherwise no. 
The Licence covers internal sharing – so for example via your secure intranet. Putting the recording on a public facing site like YouTube isn’t covered by this licence. 
Yes, a signer can accompany the words. 
Yes, the Licence covers audio recordings and AV recordings.  You can put subtitles on videos too.