Okay, I'm back(after exhaustive research, of course). As to how I knew that you're from India, in my work I have access to hidden information from all over the world, including India(except where to find good cheap classical CDs there). In this case, however, you mentioned it in a post a couple years ago.
You shouldn't necessarily drop Tower, because in-stock items are shipped to U.S addresses in not more than 10 days and their prices are lower on most items, with free shipping. They would send an email in a day or two showing CDs shipped. Any CD not shown as shipped should be cancelled, since that indicates it went out of stock and might take weeks.
On your first list of items, I'd suggest 1-6. Get the excellent Tchaikovsky collection(3.)from Amazon, because it's in stock there. On 7. you already have the Beethoven 5th, 7th and 9th, and the full set(duplicate of the 9th, item 4. on your list)isn't urgent at this time. On 8., unless you really like the Goldberg Variations I wouldn't suggest it for a first purchase. Additional suggestions(and I'll link Tower because it's easier for me to navigate)are: terrific bargain
Rachmaninoff collection ;
Hungarian Dances ; Dutoit with the Montreal in
Daphnis et Chloe ;
Berlioz collection ;
Stravinsky collection ;
Gaite Parisienne SACD ;
Roman Festivals ;
Rimsky-Korsakov collection .
Question 2.: I've had that SACD set about two years and it's excellent, but I wouldn't suggest it at that price, especially in 2-channel over headphones. If the complete ballet is necessary the
CD set is a better buy. An even better buy is the CD(5. in your first list)containing about 60% of the music.
Question 3.: The Tchaikovsky set(3., first list)includes a fine 1812. For a complete Nutcracker(not just the suite), go with
Gergiev .
Question 4.: In my view it isn't worth the extra money. The Mehta performance(1. on first list)is my favorite and much less expensive.
Question 5.: The essential cello concerto is the Dvorak, and it's coupled with Schelomo and Kol Nidrei
here .
Question 6.: An older but very fine collection collection of Strauss Waltzes and Polkas is done by
Ormandy .
Question 7.: Not enthusiastic about those mega-boxes and would pass and instead pick better individual items.
I'll stop now, but if you have any questions, ask of course.