I generally allow about 60-75 minutes for an in-park TS meal. It depends on how many courses ordered, how busy the restaurant is, how fast you eat, etc.
La Hacienda is different because you asked about watching IllumiNations from inside the restaurant. There are a few tables with an excellent view, some with an okay view, some with a limited view, and number with little or no view. If you do opt to try this, be sure to ask for a table with a view of IllumiNations and not just a window table. There are a number of window tables that face the wrong way (not towards the center of WS lagoon). Personally, I would have dinner first and then go find a spot around the lagoon to watch IllumiNations because it's pretty iffy as to whether you'll get a table with a good view or not. Otherwise, I would aim for an ADR that is 90-120 minute before the show because you might have to wait for a table (if they let you wait, you might have to take the next available table or forfeit the ADR).
