JANE:
Good Morning. I will try to answer your questions. I do not know anything about Marie Callenders lemon pie because I never tasted it. I only gave you suggestions for your consideration to modify your curd recipe to make it better. We do not know if it will until you try it first. You do have a lemon curd recipe don't you Jane,????. If not, either Gladys, Kelly, Betsy or I can post one to you.
Jane, re-read my previous post about why this type of pie weeps. Just temp. disparity between 2 recipes, the 2 temp. must equal each other in order not to induce moisture called condensation. You can keep the pie out for 5 10 minutes to settle & then place it in the refridge.
Jane, I will post a simple recipe for the "Swiss Meringue".

COMES NOW:

A swiss meringue is a heated meringue. To make one you combine the egg whites & all of the sugar in a mixer bowl & place this bowl over a pan of simmering water. Whip it like you would ordinary meringue.... Beat it till the temperature OF THE MERINGUE reaches between 130-135 degrees.. Then apply to your pie. This method will make certain the water in the whites will then evaporate, & the sugar will be melted.
Jane, good luck, & have a nice day young lady.
~CASS.