It might be, but that would require far more work than you probably are prepared to do, and I presume beyond your skillset (no offense - but if it were within your skillset, you would not have to ask probably).
It would not be worth it either way, UCI/LuCI is tied to mac80211 and related modern wireless tools, whatever DD-Wrt uses probably relies on ancient standards and kernels long phased out by now.
4.4 is not supported anymore. At least not upstream by the kernel community. You can check that easily on https://kernel.org/.
An LTS kernel merely implies it gets maintenance (bug fixes, security patches) for a more extended period, but it does not see backports in any meaningful way. So do not kid yourself: you are talking about an old kernel. And an unsupported one, in case of 4.4. 4.9 is the oldest supported LTS kernel at this point.