I don't blame you for ranting! That would be seriously annoying. Perhaps have your husband talk with his parents about their interference? You don't want to let it build up and say something out of anger later on.
Regarding the birthday party, my family (as in extended aunts, uncles, cousins) celebrated everyone's birthday ages 1 to 80. Whoever was hosting served chips & dip, some sort of candy to pick at, cake, tea, coffee, water or soda. We ate that, sang happy birthday and opened the presents or cards in front of everyone and the was end of it.
You're right, your kid won't remember turning one. I certainly don't and there are no pictures to prove a party was even had and I've managed just fine.