Wow, Jl87, just wow....
Take a breath and do not make a rush, emotional or uninformed decision on any of this. Money and greed can do strange things to people. You can always earn money and I would recommend hanging on to every possible thing you can. I have very few regrets in my life, but those I do have involve selling motorcycles. I tear up when I talk about my first Triumph and cannot even talk about the sale of my BSA Lightning, it hurts to even think about. Owning, maintaining and riding vintage motorcycles is one the best things in life and I am sure most DTT members will agree.
I also recommend the following:
Research comparable sales on the "completed" section of E-bay. Also look at recent motorcycle auctions results from in Las Vegas (Mid America and others) Use this information as a guideline only because many variables such as condition, location, time of year, scarcity will affect the price. It will give you a ballpark of where to start. We forum members always want to buy cheap and sell high and are not the best means to judge the vintage bike market.
If you need money, considering getting the bikes appraised and the go to the bank for a secured loan against the title of your bike(s).
If you must or want to sell some or all I would recommend selling the most produced, less scarce bikes on your list first. You may be able to buy one again in the future if need be. I would sell in the following in order: 1970 Kawasaki w1 Triple (right side shifter)1971 BSA 650 (oil in frame model), 1968 BSA a65, 1968 BSA Lighting 650, 1968 Norton 750, 1962 Norton Atlas in a Featherbed frame (6000 miles),1969 BSA Rocket 3 (6000 miles), 1975 Norton 850, 1970 Norton 850, 1968 Triumph Trident and then 1957 Triumph 650.
There is no such thing as a 1966 A10 BSA, they ceased production in 1962.
DO NOT sell the 1961 BSA Gold Star, despite the fact it is the most valuable bike on your list. You may not appreciate it now, but it is one of the finest motorcycles ever created, highly desirable, rare (less than 6000 made), extremely valuable and a blast to own and ride. Read my BSA Gold Star restoration thread. If you are considering selling the Goldie, see a psychiatrist to have your head examined.
Sell each bike individually.
Join britbike.com forum
Sell off some of the extra parts for cash but keep ALL tools, literature, photographs, documents etc. I am interested in BSA parts, transmissions, parts if you do sell. I would be happy to help you identify your spare parts.
Since you inherited these bikes and you are not in debt from them, store them until you make a well researched and informed decision. I am sorry for your loss, but the person who left them for you obviously had good taste and a passion for fine vintage bikes. Honor their memory by taking one out for a ride and think about what you are doing.
Good luck and keep us informed about your decision.