The template just gets you a starting point for the explanation statement. You can then edit the statement any way you want.
The calculation period for attributable earnings required to accompany the recharacterization begins on the first date that you made a contribution that you are recharacterizing, so for the contribution date I would just enter the first date you made a Roth IRA contribution for 2019, the January date, but you can edit the result to indicate the you made additional contributions during the computation period.
There is really no need to provide a reason for the recharacterization since there are no restrictions on your ability to do this recharacterization.
