I have the same question. I've been looking around and it seems that the Qlik ODBC Connector package is an OEM from SIMBA, since the only place in the web where I have found a reference to MEMLIM is in the SIMBA website. I believe that in the ORACLE documentation the MEMLIM parameter is called "Fetch Buffer Size (FBS)", but I am not 100% certain. I have looked in the ORACE ODBC documentation for other "advanced parameters" for ODBC and have not found anything relevant besides this.
Perhaps, we can ask this question to the Connectors R&D PM, his name is Alexey Dubovenko and he recently gave a very interesting presentation about this topic https://www.youtube.com/watch?v=KXJjL-dE4zQ&feature=emb_logo, but didn't go into this issue of additional parameters. Unfortunately I can't find his user name in the Qlik community.
Perhaps @Melissa_Potvin, Community Admin, can help us in relying the request for an answer to this question to Mr. Dubovenko or someone in his team.