Hi Hoa,
I believe all native speakers would, without hesitation, take it to mean he spends the day at the beach doing three different things. John likes to spend all day at the beach, sunbathing, reading, and sleeping.
If he spent all day sleeping he'd get a sunburn and not have time to read.
John likes to spend the day at the beach, where he enjoys sunbathing and reading, but sometimes wastes the whole day sleeping.
[or / and sometimes sleeping all day long.]
In this case "all day" applies to "sleeping." He enjoys doing three things at the beach: sunbathing, reading, and sleeping all day - but not necessarily at the same time. With the optional ending, he enjoys A, B, and C. In the main ending he enjoys and wastes.
The last of your group of five offerings is the only one that reads well, in my opinion, but it doesn't say he reads and sunbathes on the beach. Could be at home.
Best regards, - A.