Do I need to have all the dlc's for the ironsights to work

Nope

In fact, you don't even need RH's mod for ironsights to work. As long as the weapon models are properly aligned in Nifskope, and the 'Don't use 1st Person IS animations' is unchecked in the GECK, the game will use the ironsights view when you zoom in.
I suspect that they had originally intended on having this as a feature of the game but in the end, left it out for whatever reason.

thanks but for some reason FOOK 2 even when it said its compatible has some weird features for the energy.

how to align in nifscope is the problem for users. thus the need for a mod?

Its not particularly difficult, just time consuming.