Helpful tip: zest your lemons before you squeeze them.
Don’t want to use cream cheese? You can replace it with additional butter.
The longest I've had a Lemon Meringue Pie last in my refrigerator was about 3 days before it started to weep a little bit. So leftovers can be kept for a few days.
This lemon filling, in my opinion, is well balanced between sour and sweet. If you want your lemon filling to bend more to the side of sour, you can reduce the amount of sugar in the lemon filling to ¾ cup sugar, which will make the amount of lemon juice and added sugar equal.
Alternating between a whisk and a spatula is useful during the cooking stage because it helps ensure all of the sugar melts. Generally speaking, the egg whites should be consistently whisked while they're being heated, but occasionally scrape down the sides of the bowl with a spatula to make sure the sugar granules that naturally go up the sides are pushed down to melt. If any sugar granules get stuck to the side of the bowl they could crystalize and create hard granules in your finished meringue.