S.H.
Calico Critters doll house.
It is more pricey.
Don't get it if you don't know your kids will like a doll house.
AND keep in mind, that any pretend play toy, will get worn looking and/or broken or marked up. Kids.
If you're okay with that and don't expect it to look brand new forever, then that's good.
Or get a bunch of costumes.... for pretend play. Kids love that.
Or a play grocery cart and play plastic food and a play cash register. Kids LOVE that too, and its great for pretend play. For all. Even with you. And they can do pretend shopping and play 'store.' This teaches them all kinds of things. Pretend.
And, even if the doll house is 'big'... kids will occasionally fight. Because... they are all at different age stages and development cognitively. So, conflict will happen. But so you use it like anything else, to referee or teach them about how to play, fairly. With the child's age development, in mind.
AND most importantly, explain to the kids that it is for EVERYONE. So that, one kid doesn't claim "ownership" over it, over the others and/or get territorial over it. And EACH child, WILL want to play with it in their own way. That is a part... of what pretend play is. So keep that in mind, too.
And, you said you want the Dollhouse for your 2.5 year old. BUT that you want something for ALL the kids to play with.
SO... to me... that means... that this dollhouse, is NOT "for" your 2.5 year old. And if you tell your 2.5 year old that it is 'hers' and for 'her'... then SHE will think it is HERS. AND she may not want... to share it. She is 2. And this will create a conflict... if you then tell her that it is for everyone.
Get something else, then, for ALL the kids. A 'together' gift. With that understanding, explaining that to ALL the kids.
AND, the 2.5 year old girl and your 4 year old son... may NOT want to both play with the dollhouse. They are different ages and genders.