So when we use microbial inoculants, all those life forms are in a dormant state. The first order of business if you want the best chance of waking them up and keeping them awake is to aerate/oxygenate your solution with a bubbler, say 12 hours but don’t push it much more than that. I don’t have time for that personally. Then, the next most important thing is to keep the soil moist. That can be tricky but if you’re comfortable with it, you’re microbes are winning. If you’re doing dry backs, just forget about the molasses. Even if you wake those microbes up, they’re gonna go right back to sleep if conditions aren’t favorable. If your microbes remain dormant, molasses won’t feed them and it won’t wake them up. What negative consequences with there being molasses in the soil that isn’t actively consumed? I don’t know the answer to that. I’ve only used it outdoors.
I’ve seen that these plants will grow just fine without overly complicating things. But, I also understand things can be tweaked and improved upon. But most of those tweaks come with risks, so it’s worth studying up before potentially upsetting the balance.