I don't know where you live around town, but the $.99 Only store (several have gone out of business, but the one in The Woodlands off of Rayford/Sawdust is hughe) they have a great supply of swords that you can easily give to the princes or knights. I think boys would rather be knights while girls would rather they be princes. Also the store has a good supply of very inexpensive matching girl's costumes.
We were invited to a Little Mermaid princess once. The family hired a woman to come in and run the party. It was great, but I thought some of the things she did/provided could have easily been done by a mom that's creative and willing to put in the work. Some of us like to do these things and some of us prefer to out source. Whichever works for all is good.
The woman, decorated a child size table with white linen. Each child size chair was also covered with white chair cover that was then wrapped with jewel colored material tied with big bold flowers (sunflowers, gerber daisys of bright colors). It made for a such a drastic presentation. Very elegant. Each place setting had actual tea cups and saucers. And cupcakes, definitely cupcakes. Maybe you could decorate them individually.
She had Arial costumes for each of the girls that attended. It was great to see all the girls in matching costumes. She help the entire princess court change out of their clothes into their princess outfits. The girls loved it, she also had them place thier clothes nicely on the bed, great! She then led them out in a line and they all sat attentively while each girl got a beauty treatment; eyeshadow, blush, lipgross, and princess sparkles. Once everyone was dolled up (and the makeup was very minimal) she introduced each princess to the court individually, then they all circled around the "throne" of the birthday girl while she took her royal oath (to be a good princess, to open her presents with respect, and to be happy)she was given a tiara, and a cape. The birthday gal just loved it all, she had the biggest proud smile on her face. It was so precious. The woman also had a craft for the kids to do, and then they all sat down to have tea and cupcakes.
So you can do that.