How do I give each tab opened by a {Task} a custom name?

1) Modify contents of your task. Example:

>cmd /c RenameTab "Tab1" & tcc cdd C:\temp
cmd /k RenameTab "Tab2" & cd /d D:\
cmd /c RenameTab "Tab3" & stermc charlesr ...

And so on... Supposing, that %ConEmuBaseDir% exists in %PATH%. This can be done automatically with last ConEmu versions (option on ComSpec settings page).

More short and preferable alternative is available in build 121109 or higher

>tcc cdd C:\temp "-new_console:t:Tab1"
cmd /k cd D:\ "-new_console:t:Tab2"
stermc charles "-new_console:t:Tab3"

2) As for CD in title, you may use usual method. This works for cmd and tcc consoles. Example:

tcc prompt $E]2;"$P"$E\$P$G & cdd D:\
cmd prompt $E]2;"$P"$E\$P$G & cd /d D:\

Don't use 1 and 2 simultaneously. RenameTab has precedence!