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Prior to using your sodium bicarbonate (i.e. baking soda), water your plants thoroughly. Also, test it on a small section of plant to make sure that it doesn't suffer any bad reaction.

Add about 1 tbsp. baking soda to 4 cups of water and 1/2 tsp. of liquid soap (don't use any with bleach). Mix in a spray bottle and mist the infected plants, including the undersides of leaves. Repeat 7-10 days. Spray in the morning or evening.

Yellow leaves also can indicate a watering issue. Either to much or to little.

I would not remove any leaves until the plant begins to grow new ones.

Make sure your watering adequately.

Here is a link with growing information for squash.

https://www.gardeningknowhow.com/edible/vegetables/squash/tips-for-growing-squash.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/why-squash-leaves-turn-yellow.htm

They are most likely not being eaten. This is typical behavior for a squash plant. They will produce mostly male (non-fruiting) blossoms early in the season and will gradually start to produce more female blossoms as the season progresses. The male blossoms typically drop from the plant and seemingly disappear. Give it some time and you will see it start fruiting.

This is blossom end rot. Here is more information: https://www.gardeningknowhow.com/edible/vegetables/squash/squash-blossom-end-rot-causes-and-treatment.htm

It sounds like vine borers. This article will help:
https://www.gardeningknowhow.com/edible/vegetables/squash/squash-pests-identifying-and-preventing-squash-vine-borer.htm

It may work, but when your in an open garden there can be pollination from many sources.
There is no control. You won't know the true pollination.

Experimenting is great fun in the garden!

Yes, of course it would be edible. Enjoy.