Starting with protein and/or fat is always the way to go. If breakfast is important to you, for 16/8 you could have breakfast and lunch but no dinner, or for OMAD you could have a big ass breakfast to keep you sated all day. In my experience having two larger meals, then skipping dinner and being asleep for the second half of the fast makes it a breeze.
IF blends very well with other diets (Keto, low carb, paleo, CICO, etc). You could try 16:8 or even 14:10 and see how you feel. Some people do fine breaking their fast with a big hearty meal, others feel better more gently “waking their GI up.”
I do 16:8, eating 10:30a-6:30p, or sometimes a longer fast like not eating until 12n or 2p. I always break my fast with a cup of coffee with 1/4c milk, a scoop of whey protein, and a tablespoon of flaxseed. That gives me 28g protein, 7g carbs, and some fiber. I sip it over half an hour or so, then take some psyllium and a multivitamin. I’ve found the coffee doesn’t kick me out of ketosis, but it does energize me. After the coffee, I’m usually not hungry from a meal for another couple hours. I also usually try to workout just before I break my fast (currently 30min of shoveling/pickaxing caliche, lol).
Protein is a great start whenever you start. As for whether that has to be first thing in the morning—honestly, I think there is so much variance in individual bodies, habits, energy needs, etc, that it’s very hard to say that the exact same dietary thing (be that the food itself, the amount, the timing, whatever) is best for everyone. Personally, I gave up breakfast bc I’m rarely hungry in the mornings anyway. I’m about to enter my seventh week, and today I hit 10 lbs down. So to me, it seems like my metabolism is good with skipping breakfast! But it could be totally different for someone else. Experiment a bit and see what’s most effective for you.