Is the marriage contract formula considered sound and legitimate if the officiant first asks the husband and he signs, then goes to the guardian's assembly to ask him and he signs with the two witnesses, then goes to the wife's assembly to ask her and she signs, all at approximately the same time?

The original principle concerning the marriage contract is that the offer (ijab) and acceptance (qabul) should occur between the guardian (wali) and the husband in one sitting, in the presence of two witnesses, with the offer preceding the acceptance. However, if the acceptance precedes the offer, the contract is valid according to many jurists. It is also valid for there to be a messenger between the guardian and the husband who conveys the offer and acceptance in the presence of two witnesses, and this is considered to have the ruling of a single sitting.