You pitched too much yeast. If you had just gone with the Roselaire, it might be a little sour. The pack is designed to allow the bugs some time (not much) to increase their population before alcohol is created. Adding the additional yeast probably helped get the fermentation started, slowing down the bugs.
Either way, you should not be expecting anything for at least 6 months, and probably not until 12 before it is decently sour.
The bugs you have will work, they will just take a long time.
Adding dregs from commercial will not hurt, and may help. Some of the commercial bugs are supposedly a little more aggressive than the blends you buy.
If you want to add some more sugar, make it malto-dextrin; maybe 0.5 lbs max in 5 gallons. Don't over-do it.