Your plants look nice and green! I don't know about succulents, but for those pictured above I'd use Dynagro FP. I'm told I can use it for everything, so I do, keeps my life simple! I use it quite dilute in my watering water, which links how much fertiliser the plant gets with how much it is growing and therefore needs. So large plants, fast growing plants and plants in summer use more water therefore get more fertiliser this way, compared to small plants, slow growing plants, plants in winter.

Occasionally I flush the pots out with plain water, which rinses out mineral buildup (if there is any). If in doubt, less fert is better. Sounds like many people growing sansevieria successfully hardly ever fertilise, so maybe just use plain water for them half the time. There's usually slow release fert in the soil when you buy a plant, and mine get some when I repot as I use potting mix as the peat portion of what I mix up, but I don't think I'll rush to put any more on later.

I use FP 9-3-6 on everything I grow, though I do doctor it with added K for tomato and hibiscus, (and P early on) for tomato. It's not a matter of convenience. I wouldn't mind at all, the added effort to use several different fertilizers for different plants IF if made a recognizable difference. It just hasn't.

Al