I have a 3 year old and a 1 year old and so far I have had all birthday parties and baptism parties at my house. You didn't say if you have a girl or a boy.
For a girl, I decorated for my girl's first birthday with tons of Gerbera daisies (I bought them in bulk online and used the tons of vases that I own) in a bunch of different bright colors. The theme was really the flowers and colors. I baked the cake myself and decorated it with polka dots and used food dye to color the dots colors from the flowers. I also baked a batch of cupcakes and used the different color frostings on the cupcakes for more dots. I also went to Party City after the flowers arrived and took one of each color and found balloon colors that matched as well. It was really very simple and it turned out super cute. I had a photographer come in to take family shots and the flowers worked great as props. This would work for a baptism too, I would think. I usually have birthday parties early in the afternoon, so I have lunch type foods. I live close to Caputo's and they do great party trays. For my daughter's 3rd birthday we let her pick the food and she chose to have it catered by Pollo Campero (fried chicken, black beans and rice and plantains) and they did a very nice job. For my son's first birthday I cooked a spiral ham and put out sandwich fixings. I usually make Chex Mix and put out extra pretzels as well. I almost always have a veggie and a fruit tray.
For both of my kids baptisms I didn't do much as far as decorating. I got white table clothes. I had purchased the flowers for the church service, so I brought them home with me for centerpieces on the tables. I got a small number of white balloons to hang outside. Our church service is early in the morning, so we had brunch foods and I didn't have a lot of time to prepare the house or food. I premade an egg and a french toast casserole the night before so I just had to put them in the oven when we got home. I purchased bagels and cream cheese from Great American Bagel (I love their cream cheeses) and I purchased a fruit and dip tray from the grocery store.
Good Luck,
D.