Hey @travelersmemoire! Thank you for your contribution to @steemonob Task Request. You have done a really great job analysing the current state of code and feasibility of integration although could you please update the posts with relevant links wherever needed to verify your findings.
For the steem account creation issue, we all know that unlike the open Bazaar native currency BTC, steem accounts are not free so the default implementation will not work. Although there is a work around used by all graphene based system which bypasses the need of having a separate account for each customer. Just like bittrex and hitbtc etc, we can use a single central account to store and track all the deposits and withdrawals while identifying the users using predefined unique memos. There is an opening source script cryptotoken- exchange by @someguy123 that allows multi currency Support and we can get help from it's code on how to integrate/replace graphene based chains to RPC based chains and vice versa in any application.
Thanks again for the report. Please join us in our discord to discuss more in detail!