I don't know the Huisun cams at all but you might want to try forwarding all 3 of those ports thru your firewall to the Huisun.
80 (http or unencrypted web traffic is the function of this port)
8087 (this is a high port, above 1024, so it has no predefined function)
443 (https or encrypted web traffic is the function of this port)
Try forwarding all of those from the outside thru the firewall to the Huisun on 192.168.1.13 and see if you can connect with the phone then. Make sure the phone isn't connected to your WiFi, if you have wifi, when doing this testing. I know port 80 is currently forwarding to your hikvision at 192.168.1.11, this change is only temporary to see if you can get the Huisun to function from the outside.
If the Huisun works with all 3 ports forwarded then you can put port 80 back to the hikvision on 192.168.1.11.
You might be able to set the "service" port and "Internal" ports to different values if your firewall supports it. You could forward any port except 8087 above 1024, for example port 1025, to an internal port of 80 directed to 192.168.1.13. Then when you want to connect to the Huisun from the outside world you would just add :1025 to the end of the IP or URL you use already. So if your IP address to normally connect to your cameras at home from the outside world was, for example, 108.22.12.76 you would change it to 108.22.12.76:1025 or if you use a url such as joe.ddns.org you would change it to joe.ddns.org:1025
The reason for doing the above is to have both the device on 192.168.1.11 accessible with the normal IP or URL and the Huisun on 192.168.1.13 accessible at the same time with the normal IP:1025 or URL:1025
I see in your image of the firewall screen you are also forwarding ports 8000 and 8112 to the Huisun, why forward those ports? where did you get those port numbers from to forward them ?
The port forwarding I mentioned above with 1025 would look a bit like this in your Firewall window:
ID....Service Port.......Internal Port.....IP Address.........Protocol.....Status
6......1025.................80...................192.168.1.13......All.............Enabled
(edit for formatting to try to make the example more understandable)
