It might be helpful and make it easier for folks to offer you advice if you would clarify a few things. And forgive me if I missed this in your other thread that is on this subject, but I don't recall seeing these things spelled out:
Do you have a budgeted number of dollars ?
What specifically are you trying to accomplish ?
In other words, how many lights do you want to buy/use within this budget ?
What specific modifiers do you plan on using ?
Is it important that you use this common equipment in your studio and also
for location shoots, or can you have separate gear to take to location ?
If you could answer these questions, then it would be easier for folks here to give specific recommendations.
Part of my logic in asking these questions in this way, is because to be honest, the mix of lighting gear you have looks to me to be a rather confused mix that would be difficult at best to make a coordinated effort with. For instance, personally, in the AB line, I would not have chosen a B400 to shoot alongside a B1600....and I think your comments in the thread have shown that this is a combo that gives you frustration. Honestly the 1600 is most likely more power than you reasonably need for much of your indoor needs, so you end up with these issues of not being able to throttle back the power enough. And then on the same set, you have a B400, that may or may not have enough power, depending on what modifier you need to use for a given situation....so you end up compromising other aspects of the creative lighting by moving the light closer or farther from the subject. Depending on what you are trying to accomplish, this may work, or it may give you a quality of of light that is not what you want. Do you see what I mean ? So for instance....let's just talk about the AB line because that is all I own, so it's really all I can give direct use comment on. Suppose you had two B800's in place of your 400 and 1600. See where I'm going with this ? You would have a matched set, power wise, then you might be able to more easily deal with light output issues. It also makes the model lights matched in a way that makes it easier to use them to visualize what your final outcome is going to be.
I suspect the same would hold true if you had Elinchrom, or any other brand....if you have wildly differing outputs from these various sources, it is more to think about during setup, and more to deal with if/when you change things up on the set during a shoot.
I don't even want to think about the headaches you are encountering due to trying to integrate these small, low output speedlights in the same set.
So if you could, try to answer those specific questions, and also think about what modifiers you now have, and what of that will be usable depending on how you change up your gear. Because as you know, modifiers, stands, triggers, etc all need to be factored in to the budget.
On the other hand, if you have a very high dollar figure as for budget, then this would open a LOT more possibilities.