Validity of a Contract - Signed in two different locations

Greetings Ld Professionals, I have come across a situation where one party is supposed to enter into a SPA with the buyers. Here buyers are from Germany. Hence the instructions received were to send across the scanned copy of signed SPA's by the sellers via to buyers and the buyers will print the copy of the same and sign it. Is this valid ? There is a clause about counterparts in the SPA empowering to execute the agreement in one or more counterparts which shall all together constitute effective agreement and the date of sending the scanned copy of the agreement (Email Transmission) shall be taken/considered as effective date of signing of the SPA. However there is no mention about counter part signature anywhere in the SPA apart from the above clause. And further, no mention even at the place of signature of the German buyer. It is just normally signed in a separate sheet under the name of the party. Is there any specific requirement ot execute the contract in counter parts ? Further, every page of the contract is signed only by one party ? I understand that there is no hard and fast rule for initialling in every pages. But what if only one party alone initialls ? How to insist the same if it is in counter part execution ? Further again, There are 5 sellers and only seller is initialling in every page. Will this be right ? Tons of thanks to you in advance Regards Prakash