For our pale solera barrel we are planning on cycling 1/3 of the beer each year. This will eventually give us a blend with an average age of 3 years. Here is a spreadsheet I came up with to help figure out what the different variables do to the average age of the blend: http://www.archive.org/details/SoleraAgingSpreadsheet
1 year old sour beer can be quite good, but it will depend on how fermentable the wort going into the system is. If you are doing a turbid mash it may take more than a year for the gravity to stabilize, but for a simple infusion mash you should be fine.
Not sure if the lactic acid bacteria will dominate or not, that is more in the short term. After a year the Brett will be the dominant microbe (probably).
Watch out for using a bucket, some people suggest that they let in too much oxygen leding to acetic character. I haven't used them, but it is something to be aware of.
Yeast autolysis can be an issue, so after a couple years you may want to rack off into a clean ferementer (much easier for you than for us...).
You are probably being too ambitious with the number of different things you are hoping to do, but if it tastes great I'm sure you'll find room for a second solera.
Hope that helps, good luck.