I am in pretty much the same position with my second year batch made in May 2014 and ready to be blended with some of my first year batch later this year (10 gallons in June 2013 split between glass carboy and 5 gallon bourbon barrel). I blended portions of the first batch at about a 1:5 ratio for bottling for comps and kegging in a 3 gallon cornie. Then I filled the barrel with the rest of the carboy - I didn't add new dregs to the barrel, but you can, if you think it isn't enough. As the barrel ages, it likely will not need dregs, because the bugs will be in the wood. Some guys do a lactic sour mash to prep the wort from a souring perspective, because the lacto loses some punch to the Brett and pedio over time, but I haven't found the need (I used a new couple vials of Roeselaere for the 5 gallon batch this past May). I didn't pitch any extra Sacc, either, because the fresh vials had enough Sacc for the primary IMO. One other thought is fruit - I have some tart cherry wine base that I intend to add into the mix on the next blend, just for grins. Have fun and remember, it's a hobby.