Do I need to leave some extra space available on the disk which my database log files reside, for log backup operations to successfully occur? If I size my log files to evenly split the entire drive they reside on, leaving no extra space available, will log backups still be able to occur successfully?  I have several databases, with one log file per database.

Is it good practice to not leave any space on the drive available, i.e. allocate it all to the log files? (The drive is dedicated to the log files in this case, data and the OS live on their own partitions.)
Well log backups don't change the size of the log file, and the only reason you'd need space on that drive is if you were backing up the log there (which is the same kind of bad idea as putting your house key and the backup on the same key ring). But a slightly different question, do you expect none of your log files to ever grow? Leaving a bit of space at least gives you some canary time where you can deal with a log file that is growing atypically. With no space leftover, as soon as the log file needs to grow, you're down.