Secondary stalled fermentation?

I brewed in a 6 gallon carboy, and waited 2 weeks for it to ferment. It appeared to have stopped. At that point, I siphoned it into 3 smaller containers, to add flavors and make 3 distinct beers. I was careful not to include any of the bottom sludge or top yeast mess. One of the secondaries, I added more sugars. Molasses, and dark candy syrup. For the next 3 days, nothing.

So, some newbie questions:
1) It is still fermenting, correct? Just very slowly? Maybe add a little more yeast to jumpstart it?
2) What do I do differently to avoid adding yeast next time? Do I just make to syphon some of the top or bottom sludge along with the clear beer, if I'm adding fermentables?
3) The other two secondaries have no sugars and are ready to be bottled. Do I need to add yeast, or is there still enough surviving to carbonate?


So basically, my questions relate to surviving yeast after fermentation is complete. I'm guessing enough are alive and floating around the clear liquid to carbonate, but not enough to restart fermentation if I add a large quantity of sugar?

The only real way to know if it's fermenting is to have taken a gravity reading with a hydrometer after the boil and then compare it to a reading taken after the 2 weeks of fermentation.

If you had a healthy primary fermentation, there will be plenty of yeast left in suspension to ferment any additional fermentables (up to a point).

It looks like my question answered itself. At 4 days later, I noticed the other two secondaries (with no added sugars) had a healthy froth up top. This tells me two things:
1) I switched to secondary too early. I should wait for the primary fermentation to clean up first.
2) I transferred yeast, but not many. They needed a few days to regroup and repopulate.

Do higher gravity brews take longer for visible fermentation? I'm wondering if the yeast are just slower to populate and work because they're drowning in sugar. I added half a packet of yeast and now I see some sludge forming at the bottom. Just nothing at the top like the other carboys.

Just cuz I'm curious.....why were you adding more fermentables when you transferred to a secondary vessel?

Experimentation, mainly. I don't want 5 gallons of the same thing. I split it into 3 sub-brews. One is plain, the other is peel/coriander, and the third is a darker attempt with molasses and candi sugar, then some fruit spices.

It's a gluten free attempt for my friend. I wanted to see if it was possible to make a darker beer off a sorghum base, but didn't want 55 beers like that.