The 1.4 looks amazing but if someone walks even a foot forward or back they will become out of focus...any lens that can still give a good bokah effect but will give me a lot more leway with the actors staying in focus?
Unfortunately no - at least in the sense that you can't have both the same bokeh and the ability to keep your actors in focus when they move. You can reduce the aperture on your existing lens, which will increase the depth of field and give you more leeway in terms of keeping actors in focus, but by doing so you will also bring background elements into sharper focus and lose some of the background blur.
There is no lens that can magically do both, but through changes in composition you may be able to achieve both. Apparent DOF is affected by a combination of the focal length of the lens, the distance of the lens to the subject, the lens aperture, the focus distance, and the distance to the background. To achieve what you're looking for you'll need some combination of moving the subject farther from the lens (which may require a longer lens focal length to frame the subject as desired), reducing the aperture, and composing with a background that is farther away from the subject.
Using a depth of field calculator can help you figure out what's possible:
http://www.dofmaster.com/dofjs.html
So you may not be able to achieve it indoors because you just won't have enough distance between the camera, subject and background to do this. For instance, a 50mm lens at f/1.4 with the subject 10 feet away will give you just 3 inches of focus range in front and back of the subject. If your room is only 20ft wide there's just not enough space to change your composition. Dropping the aperture to f/8 will give you a foot or two of leeway on either side of the subject, but will also significantly reduce the bokeh effect of elements in the background because they aren't far off from the focus point.
Outdoors you should be able to do it though. With a 50mm lens at f/1.4 and the subject at 30 feet from the camera you'll get several feet of leeway on the focus. Now if your subject is standing in front of a wall it'll be in focus as well, so you won't get the bokeh you're looking for, but if you're background is far away - streetlights in the distance, for example - you will get it.
Of course the problem is you won't be able to get close ups that way, so you'll need to experiment to find the combo that works. Bring the camera back to 10 feet from the subject, drop the aperture to f/5.6 and compose with a distant background, and you'll get a combination that likely gives you good soft focus on the background while also providing a couple feet of leeway in terms of actors movement.
As you do this though you may also see the quality of the bokeh change depending on your lens. Some lenses have as many as nine blades in the aperture and will retain a smooth, circular shape to the bokeh throughout most of their aperture range. Others (generally less expensive lenses) will use as few as five blades and the bokeh will take on a geometric shape like a hexagon (actual shape depends on the number of blades).
