1. Acros As darngooddesign said, Acros requires the bigger sensor in the X-Pro2 and X-T2. However, all Acros is is the standard monochrome profile with an 'S' shape tone curve applied, and then some fake 'grain'. You can apply these same adjustments to a raw file in Lightroom using the Tone Curve (select 'medium contrast') and Effects panels for grain, or of course you can take the photo in Photoshop for more careful editing. Other software will have similar options, if you don't use Lightroom.
2. I've not noticed a change in speed myself, but you're not the only person who has said the write speeds seem to be slower. Might be a problem with only certain brands of memory card? I'm not sure.
3. The front dial always controls two things—by default, shutter speed and ISO—so yes, you do have to push the dial in to access ISO. Simply turning it without pushing it in will change the shutter speed up or down in 1/3rd stops, but if you want to change shutter speed by a full stop or more then you have to do that with the shutter dial on the top of the camera.
However, if you set the top shutter dial to 'T', then the front dial can control the shutter speed freely, up and down as much as you want. You still push the front dial in to access ISO control.
You can also change the control when you push in the front dial. If you open the main camera menu and go to the second system settings menu (blue 2), you'll see an option called 'button/dial setting'. In there, go to 'function (fn) setting'. The second button, Fn2, is the front dial when pressed in. You can change that to whatever you like, and move ISO to one of the other function buttons. (Some function buttons are disabled depending on what focus mode you're using.)
4. There's an easier way to solve this fourth problem. If you turn the camera to manual focus, you can then press the AF-L button to start autofocus. When you stop pressing the AF-L button, autofocus stops and the camera won't change focus. This is called 'back button focus' on most cameras; Fuji just make it part of the manual focus behaviour. So you point the camera at whatever you want to focus at, press the AF-L button to autofocus, then let go fo the button and now the focus stays where it is, no matter how many times you press the shutter. No need to hold a button to hold focus; you can let go and focus doesn't move. The only drawback is you have to remember to press the AF-L button, because half-pressing the shutter will no longer trigger autofocus at all. It takes a little while to get used to, but once you learn it, it'll be no problem and you'll wonder how you ever used a camera without it.
