My fiance's brother and sister-in-law were up for Christmas and their four children are in our wedding. I was looking online with my future mother-in-law and sister-in-law at dresses for the two girls. I found two nice, but not expensive flower girls dresses on Amazon for them. My mother-in-law offered to buy them. She wanted to make the dresses since she loves sewing, but I vetoed that idea. The topic of outfits for their two sons came up and my future sister-in-law mentioned that they plan on taking the boys to Macy's to get button down shirts and dress pants. The older boy will be 15 at the time of our wedding and the younger boy will be 3. My fiance and I already picked out tuxes for them as the rest of the bridal party will be in tuxes since our wedding is a formal event. I told my future sister-in-law this and she seemed shocked that we want them to match what the other people in the bridal party are wearing and she also seemed upset that we thought they would pay for the boys outfits. I thought my fiance had talked to his brother about all of this so I felt super awkward mentioning all of this to my future sister-in-law. I told them I would talk to my fiance. I definitely don't want to change what they wear because they wouldn't match the rest of the bridal party. My future sister-in-law already mentioned wanting the girls to have their hair and makeup professionally done which I personally don't feel is necessary for a 4 and 6 year old to have their makeup professionally done, but that's what the mom wants. I feel like rather than spending the money on that the money could go towards the tuxes, but I know I can't tell them how to spend their money.Note: I am paying for the flower girl baskets, ring bearer pillows, and crowns I found for the girls hair. We are also buying gifts for the kids as a thank you for being in our wedding. My fiance mentioned possibly paying for the girls hair and makeup as their gift even though I think having it professionally done is unnecessary. I would rather buy them something small they could play with. Who normally pays for all of this stuff?