Flaws?

I recently designed a small business network for about 50 nodes across 2 floors at about 107ft long. 2f has about 21 nodes while 1f has about 29 nodes inclusive of ip cameras. What I did was, set a switch and patch panel in the existing server room on 2f, ran 2 fiber cable to 1f that has 2 switches and a 48P patch panel. So both switches are connected via fiber cable, where the 2f switch connects to my firewall. Now, the client has decided that every machine needs additional cables to facilitate printers, keypads and card makers. The cable run has been completed and adding 17 cables would cause a mess to rerun. So instead at each cubicle, i decided to use dummy switches to add connections to the additional hardware. My main switches are Cisco SG300 28P x3 and the dummy switches are TP-Link 5 port smart switches.

In the above topology, will the switch to switch cause any problems? Considering that the Cisco switches have STP enabled.