Hi!
1) Can you buy SE Vol. 2 GUITARS & KEYBOARDS Vienna Instruments Collection (https://www.vsl.co.at/de/Special_Edition_Vol2/SE_Vol2_Percussion) without owning SE Vol. 2 or is it required? I own Special Edition Vol. 1 and Special Edition Vol. 2 Plus. Having the harpsichord AND the organ would be great but the low price of 50€ for both + two guitars sounds like you need SE Vol. 2.
Moreover, the harpsichord alone is 55€ (https://www.vsl.co.at/de/Special_Keyboards/Harpsichord).
In short, can you only buy SE Vol. 2 GUITARS & KEYBOARDS and just that or only if you own SE Vol. 2 (strings etc.)?
2) I have another question on strings in general. My Special Edition Vol. 1 & Plus contains many articulations. Why would you buy Vol. 2, 3 or 4? New instruments are nice (or articulations) but I don't understand the different setups (strings with 6 musicians, strings with 14 musicians etc.)? Why do you need that? You can compose a piece of work, instrument per instrument...and have 6 violins for example. Why do you need to buy a new library with a patch for 6 violins? Because of doubling and 6 real violins recorded at the same time sound better than one violin you use on different tracks in your project?