The bug was fixed (I just tested it again, to be sure), so if you still have an issue, it's probably something else... Note that voice service is ran by another provider than LL, and may sometimes have glitches or go off...
I don't have a single clue about what you are speaking about... Please, give precise repro steps as well as the logs. Also, be aware that the "Active speakers" (if it is what you are speaking about) list is not filling up instantaneously: it may take several seconds to one or two minutes to fill up, depending on how fast SL is replying to the viewer to name requests and on how many speakers are around.
Again, there are delays that are absolutely normal (the voice client must connect to the voice server, which itself might take some time to respond, depending on its own lag). Again, without the logs, it's impossible to say if you encountered a bug or just normal delays...
This has nothing to do with voice... To get the chat input line, simply uncheck "Use the old style chat history" box in the "Preferences" floater, "Cool features", "User Interface" sub-tab, and restart the viewer.
Nothing changed on that account between v1.26.3 and v1.26.4, so if you see things differently on your system, it's something to do with your system (new drivers ?), or different settings in use (for memory exhaustion and blurry textures, it could happen sooner if the "Advanced" -> "Allow Swapping" setting is unchecked).
On 64bits systems (or on 32bits systems with PAE) that got over 4Gb of RAM, you can still run out of memory in the viewer (or any 32bits application) when reaching 4Gb (3Gb on 32bits systems with PAE since 1Gb is reserved to the OS on them) of used virtual space (this is because 32bits applications can't address more than 4Gb). The Cool VL Viewer got a memory usage indicator in the status bar: when it turns yellow, the viewer starts increasing the "discard level" for textures, meaning some textures will blur a bit (but if there's a texture you want to see at full resolution, you can still hover the mouse pointer on the object that uses this texture to get it to load fully). This was explained in details in
this thread.
If you want to help, please do check for the replies I already gave in the forum (here, both the chat input line and memory stuff have already been dealt with and explained in the
FAQ and general help forum): I hate repeating myself and loosing my time doing so (the more time lost replying again and again to the same questions and the less time is left for me to address true issues and to code the viewer)...