Not really. The option file contains basically no textures as far as I know, only a few emblems or such that you can use when editing a ML team kit for example.
The option file is there to keep track of player settings, aswell as store name changes and ability changes you have done to players (for example giving Classic Team players proper names instead of the made-up default ones).
I guess you could say that the option file provides a layer of customizability for the static databases and such that is the .asf files in the "dat" folder.
All data are stored in those .asf files, including textures for kits, player databases with all the player stats and info (that can be modified with the option file) and balls, pitch-textures etc.
Using different option files can basically give you altered/corrected team and player names, aswell as PES/WE Shop items unlocked, and basic transfers to reflect the latest real-world player transfers between clubs.
If you want to use different balls, pitches, stadiums, and such, you will need to patch the .asf-files.
Also, a patch usually comes with an option file that has been created to reflect any changes that could be in the patch, for example players might have swapped position, different stadium names, and such.
As for what patch is the best, PowerPatch is quite good I believe, and Superpatch aswell. Not sure what work for PES and what for WE, or if they work for PS2 versions etc.
www.pesinsight.com has a download-section that has most patches (that I know of) stored.
And I haven't player WE10 so I cannot answer the 2nd question.
