how to use multichain blockchain and smart contract for real world use case

Question

use case -

we have two actor lets say merchant and customer. both merchant and customer register themselves on blockchain (only basic info, private key gets stored on centralized DB).

 merchant create proposal for asset including (price,harvest date,quantity,commision etc) on multichain blockchain,our team verifies that proposal and update the status of asset to verified.

now in our marketplace we show list of assets with the status of verified and customer can buy those asset proposal

question 1- do i need to create stream for merchant and customer ?

question 2- do i have to call high level api "issue" to create an asset or should i create an asset in stream. which one is better way?

question 3 i need a smart contract which will run whenever any proposal gets purchased by customer. job of smart contract is to transfer the fund by calling external service.but i think smart contract is not a good choice if it has to be dependent on other service.

Answer 1

1) Yes you can create a stream to show merchant and customer details.

2) I think you should use "issue" to create the asset, if you want it to represent units that are transferred between blockchain participants. The approval of the asset can be done in a stream, so anyone can check for that approval.

3) Smart contracts cannot call external services in any blockchain, so you need someone watching the chain and performing the fund transfer as the appropriate time.