Alistair dialog patch - not working

You didn't say whether you used the .dazip version. theskymoves is correct, if you installed the .dazip version of the Alistair mod, then you need to examine the list of files LadyOlivia changed, and remove those from ZDF and Mild Romance. I've never used LadyOlivia's file either, but I have used "Improved Romance Scenes - Alistair" with "Mild Romance Scenes (MRS)", "ZDF", and "Morrigan Restoration Patch". If "Alistair Dialog Patch" worked for you before, you must have removed the conflicting files from "MRS".

Sometimes what I do when I want to make sure Mod A takes precedence over Mod B, I'll rename the folder in ...core/override. The folder for "Alistair dialog patch" becomes "zz-Alistair dialog patch" (I'm assuming the manual installation is all override). Since DAO checks the override in reverse alphabetical order, any files in this folder will be used and the ones in "MRS" with the same name will be ignored.

I don't know if you use DAMM (Dragon Age Mod Manager), but it does have a create .override feature. If you use the manual installation of "ADP", then you can combine it with the other mods in DAMM to create a new .override file. If you have conflicting files, you won't be able to create the .override. The advantage to this is that once you create it, you won't have to recreate for later playthroughs.

They will work for a Leliana romance. I have to do the same thing when I use IRS-A with MRS, delete the Alistair_main files from MRS. At least one of IRS-A, MRS, or ZDF has instructions on how to make them compatible. I would suggest checking the instructions for those mods to get some light on how to make Alistair dialog patch compatible.