How to understand みんなしてお出かけですか?

Question

I have seen some cases where して is placed before a する verb:

1) みんなしてお出かけですか？

2) みんなして大好評だな

Is this regular practice? Is this grammatically correct? Can this be done with other conjugations of する?

Answer 1

What you're seeing is not お出かけする written in a strange order, but a fixed adverbial phrase みんなして ("get together and (do ～)", "with many others", 一緒になって, 集まって). 大好評 is not a suru-verb in the first place. みんなして doesn't have to be followed by another suru-verb. For example みんなして同じ事を言う means everyone says the same thing almost at the same time (=口を揃えて言う).

You cannot use みんな as a regular suru-verb. みんなして is a fixed expression derived from archaic Japanese, and it always appears exactly in this form. In archaic Japanese, して was used like a standalone particle similar to で in modern Japanese. See this and this. 三人して meant 三人で, 血して書く meant 血で書く/血を使って書く. You may still see this type of して in literary sentences. みんなして doesn't sound particularly archaic to me.

二人して is also used in modern casual conversations (e.g., ねえ、二人して何やってるの？).

Answer 2

して is the verb する which have been conjugated in its て form to connect the 2 parts of the sentences. The fact that the second sentence part of your sentence starts with a する verb or not is pretty much irrelevant.

こうする

Do like that.

こうして安全だ

Do it like that, it's safer.

Other way you can conjugate する in such a way.

こうしたら、安全だ
If you do it like that, it's safe.