The answer is 'yes' for watching 3D movies or programs, and 'no' for conventional 2D shows. Almost every 3D TV model in the market is able to display images in 2D or 3D mode. Some sets are able to convert 2D sources to 3D as well. Glasses (regardless of active or passive types) are only required for viewing 3D content.
Again, this isn't entirely correct. While many premium models like Panasonic's V series and Samsung's Series 8 are capable of converting 2D signals to 3D on the fly, some of the mid-range models are only able to display content strictly in 2D or 3D mode without any conversion features.
Active and passive 3D displays are compatible with most brands' Blu-ray players, as long as the BD players themselves are 3D-capable. There shouldn't be an issue as long as the Blu-ray deck is capable of decoding the MPEG4-MVC (Multiview Video Coding) format used by 3D Blu-ray discs.
This is incorrect. Reason being that active-shutter glasses are based on IR (infrared) or RF (radio frequency) protocols, while others are using Bluetooth technology (like some of Samsung's recent 3D eyewear). It's best to use the brand's recommended glasses.
Apart from the Sony PlayStation 3, the HDMI standard is determined by hardware components and cannot be upgraded by a simple firmware upgrade. You'll need an entirely new chip for HDMI 1.4.
Both 3D-ready and Full 3D operate in a similar fashion. And they also utilize the same alternate frame sequencing technology and the use of active-shutter glasses. However, there are some older 3D-ready models which require an external IR syncing transmitter. On the other hand, Full 3D TV sets typically come with integrated transmitters.
Crosstalk or ghosting happens when shutter lenses fail to block light from entering the respective eye when it isn't supposed to. Alternatively, an LCD panel's slower pixel response time also leads to crosstalk. In other words, "double images" may appear when the pixels take longer to change their display state. Current LCD panels have an average response time ranging from 2 to 4 milliseconds.
Plasma displays are better off in that they have a faster (0.001ms) response time. However, PDPs aren't totally free of crosstalk, since the "phosphor-lag" phenomenon may produce crosstalk effects too. Recent models such as Panasonic's V-series with their rapid decay time phosphors can help mitigate this.