What formual to use in order to have tasks written in front of corresponding name

This is quite tedious but I think I've managed to get what you want. I needed to create an extra table as a helper section to keep my formula sane.

The helper table basically calculates the number of tasks a particular person has on each date. Then, to generate the list of tasks for each person, I used...

Formula:

=IF(C18=0,"N/A",INDEX('List A'!$A$7:$A$26,MATCH(SMALL(INDEX((('List A'!B$7:B$26<>$B10)*1000)+ROW('List A'!B$7:B$26),0),1),INDEX(ROW('List A'!B$7:B$26),0),0))) &

IF(C18>1,", " & INDEX('List A'!$A$7:$A$26,MATCH(SMALL(INDEX((('List A'!B$7:B$26<>$B10)*1000)+ROW('List A'!B$7:B$26),0),2),INDEX(ROW('List A'!B$7:B$26),0),0)),"") &

IF(C18>2,", " & INDEX('List A'!$A$7:$A$26,MATCH(SMALL(INDEX((('List A'!B$7:B$26<>$B10)*1000)+ROW('List A'!B$7:B$26),0),3),INDEX(ROW('List A'!B$7:B$26),0),0)),"") &

IF(C18>3,", " & INDEX('List A'!$A$7:$A$26,MATCH(SMALL(INDEX((('List A'!B$7:B$26<>$B10)*1000)+ROW('List A'!B$7:B$26),0),4),INDEX(ROW('List A'!B$7:B$26),0),0)),"") &

IF(C18>4,", " & INDEX('List A'!$A$7:$A$26,MATCH(SMALL(INDEX((('List A'!B$7:B$26<>$B10)*1000)+ROW('List A'!B$7:B$26),0),5),INDEX(ROW('List A'!B$7:B$26),0),0)),"") &

IF(C18>5,"...","")

NOTE: I've also capped the number of tasks to 5 to keep the formulas sane, but it shouldn't be too difficult to extend them to higher numbers.

See attached.