Either way you are going to run into restrictions. If you want to use the hotspot functionality then you need the MikroTik to be a layer3 hop for the guests. This isn’t a huge problem, but something to be aware of. You can still use the proxy functionality with the hotspot if you desire.
If you just want it to filter certain websites, you’ll still run into a problem as well with using transparent proxy. A transparent proxy can only redirect HTTP requests and work. This means any HTTPS sites can still be accessed just fine. Also the processing power may not be enough to handle the proxy in a 750 depending on the size of the network and how much traffic will be going over it. A dedicated full featured proxy server may be a better solution for you depending on the needs.
This is just the hotspot setup I was hoping to achieve.
After reading from the wiki and double checking with the techsupport that having hotspot on a bridged interface is possible I have failed to make it work.
In linux there is a way to block access on bridge by mac addresses with ebtables I think.
Is there a way to use routeros hotspot without creating another nat and dhcp disrupting the existing network as little as possible?