You do NOT have to invite all the siblings. Just 'his' friends.
It is not like you have to invite the whole family of each friend.
I don't do that... my friends don't do that.
ONLY if it is a close family friend, do we/I include the siblings.
And you do NOT have to invite BOTH parents and their kids. ONLY 1 parent...
This is the way, me/my friends and the parents of my kids friends do it:
For example:
On the invitation say: "you and 1 parent are invited to help celebrate Johnny's Birthday..... it will start at 11:00 and end at 1:00pm...."
etc.
The thing is, you are making a party for your son... not for all his friends and their family. It is for your SON and his 4 friends. That is normal... to just invite HIS friends. That is the way we do it, and lots of our friends do it... it is typical. In fact, it is NOT "expected" that a birthday party HAS TO include their friends and parents and their babies.
You can just have the party at a park.
Or at home in your yard.
You simply say certain rooms are off limits.
And the kids can only eat, in a certain room... not roam around with food in their hands. And put down drop-cloths on the floor... make it fun... like camping. Just good ol' painters drop-cloths. Its not expensive.
Kids that age, entertain themselves quite well... it does not have to be complicated or 'engineered'... maybe treasure hunt games, a pinata, cake, finger foods, a "cupcake" cake.... balls & a decorated box for them to throw the ball into from behind a line and they get prizes etc. .. "Simon Says"... spoon and egg games.. they hold a boiled egg in a wooden spoon and try to be the first one at the finish-line etc., or roll the egg with a wooden spoon across the grass to the finish line... EASY FUN games... not expensive.
Simple things.
No need to hire 'expensive' entertainment....
You don't have to have 'candy' at the party besides the cake etc. Just good ol' normal finger food... meatballs, mini burgers, chicken nuggets, roll-ups, pizza, cut up fruit, dips etc. No need for lollipops etc.
Cover your dining chairs, with pillow cases... it can slip over the chair back and put it on the cushion as well. That's what I do when I have mega-lots of kids over at my house for play-dates. Or, I simply tell the kids, nicely, DO NOT go in certain rooms... or I put "fun" signs.... in certain rooms, as a head's up or mark it 'private.'
I... tend to have lots of play-dates for my kids... MEGA lots of kids at one time... like 6 kids plus my own and their siblings. I DO NOT have a messed up house or 'disaster' afterward. Because, I do, what I mentioned here.
www.orientaltrading.com has lots of cheap/fun party games and goodies. Teachers use this site as well.
all the best,
Susan