Internet Distribution for a Mall

Hi guys! I'm new here. Hope you can help me.

The management want to distribute internet thru different tenants with limited bandwidth.

We already have edge router as our main router. We also have 100 mbps internet up and down.

Here is what I plan to execute:

(ISP 100mbps) > (edge router)> limiting (using basic queue feature @ 5mbps) targeting IP address > switch(unmanaged) > CAT5e cable using (will be using it together with intercom/phone line) (see attached image)> Tenants Router(with own dhcp server)[end]

Question:

1. Will I encounter any problem with this?
2. Do I need to use Managed Switch?
3. I plan to use /23 subnet on one VLAN, am I wrong to do this?
4. Using the "Basic Queue" feature of the edge router, will the users(child IP) on the sharing on the IP address(parent IP) be sharing the single 5mbps bandwidth or every user will have 5mbps individual speed and will be sucking the bandwidth from the ISP(100 mbps)