And Howdy to you too! Welcome to the site.
Don't worry, all will be made clear by the flight staff when you board.
8a is a great seat, and you have clearly been looking at our seat guide. Glad it was of use. I assume you can pre-request your choice of seat at
http://www.virgin-atlantic.com with your e-ticket number or confirmation number. Of course it may change on the day, but that is unlikely.
Once you have taken your seat the In Flight Beauty Therapist will come and talk you through the treatments available. The IFBT has a quota for health and safety reasons, and this may mean she cannot do all the treatments. There is some discussion on the site about which is best. The massage is quite good, although not strong enough for some. Because it is the most popular I suspect, and because it is very clearly on quota, it seems to be the one where there is the highest chance of not getting your treatment. The "Hot hands" maybe a little girly for you, but you stand a better chance of getting the treatment. For my money it is the one I would go for. There are some others, which are aimed much more at the cleanse and tone end of the market if I recall correctly.
The Senior supervisor should also introduce them self near the start of the flight. Do make sure you ask him or her any questions you have.
You can eat anything you want at any time, although you may get the impression that the crew would like you to eat in the main meal serving! If that is not when you want to eat, just let them know and it will be fine.
The 346 whould have V-port which is a really good on demand entertainment system. There is a description of its function on this site, and on the virgin site you can get a preview of some of the film billing. However on your flight there will be a much larger, indeed huge, choice of films and TV programs. There genuinely is something for everyone I think.
The Bar is a great place to chat to crew and other pax. Oh, and for a drink!
Soon after boarding, if it is a night flight, you will be offered a sleep suit. If it is a day flight you can request one whenever you want. Most people tend to change into it early on so that clothes do not get creased, or have G&T spilt on them

There is a lengthy debate on the site about the amenity kit, which has unfortunately been cut back (to proportions that any accountant would have to call magnificent). There are extra supplies in the loo, and you may want to grab what extras you need early in the flight, as there have been some reports of extras running out fairly quickly. This is of course exactly what VS did not intend to happen, but IMO pretty predictable with human nature being what it is.
Afraid I am not able to help on the lounges, but someone will be along who can. It may take a couple of days as it is a Sunday today and the site is not normally that busy.