The directions for celebrating the Lord's Supper are clearly given at 1 Corinthians 11:23-25, moshe. There is no need to have the bread blessed beforehand. I don't know Jewish custom with respect to celebrating Passover or eating a seder meal, but those customs would not be binding on Christians in any case. The entire "menu" is simply unleavened bread--something anybody can bake--and wine. Christ said a blessing over the bread and wine before passing them around. There is no indication that he had someone else bless them and Paul did not say that these items had to be blessed ahead of time either. Instead, he directs that any blessing said would be done at the time of the celebration and not before.
As for the necessity to have Passover matzah, again this is a Jewish custom and understanding. That would certainly not be binding on Christians. Unleavened bread was commanded to be used at Passover celebrations. No sourdough or any other kind of leavened bread was to be eaten during the meal or the entire seven days of the Passover festival for that matter. It is important to remember that this is a Christian ritual, not a Jewish one. So there is no need to follow strict Jewish belief, practice or regulation in holding the ceremony. Simple unleavened bread along with wine is all that is necessary, not kosher matzah and kosher wine. And the celebrants can ask any blessing they see fit.
Quendi