I am not cutting, but I am curious to know the answer to this question for when I do.

Is it full body training multiple times per week? Upper/Lower split? Bodypart split? Other?

What do you think and why..?

Doesn't matter whether you are doing full body, upper/lower, or a split because you'd be working the same muscle group the same amount of times each week.

Lifting intense and heavy.

Any or all of those. Pretty much whatever works for you is what is best. There is no right way and you will find people who have had their best results doing all sorts of different stuff.

This is where the art of training comes in. I actually had a conversation on Saturday with a guy about this.

Science gives us a broad and basic outline, but that is all. The rest is an organic and artful manipulation over variables that work well for you. As you try more and more training styles and ideas you will have a better and better understanding of what your body needs. You will then start following what your "gut feeling" on what you need to do and implement training that way.

Example. One of my training partners trains 2 or 3 days per week. Most of his workouts are whatever he feels he needs (from exercise selection to decisions about volume) and he only trains up to heavy weight every 6 weeks or so.

I train 4-6 days per week. The similarity between my training partner and I is that we both do whatever we feel is best for us on that training day. After that, I train heavier every 2 or 3 weeks, much more frequently and my volume is higher.

Both of us have good results. I can't understand how someone who trains so little can get results. He can't understand how someone who trains so much doesn't get hurt all the time.

Suffice it to say that my training style will not work well for him and his training style will not work for me. (we know because we have gone through some phases where we have tried)

Now, though this is not a story specific to cutting, the moral is the same. There is no best way, only your best way. This is the art of training yourself, there is only one way to learn now to do that. Try stuff.

im very curious to a suggestion on this also.

i believe it is the best to lift heavy, but not as intense as you would during a bulk b/c your body doesnt have the calories it needs to rebuild as well.
i think lower volume, heavy training is logical for a bulk. as long as you keep the strength, the muscle is likely there with it(well most of it).

as long as your using your muscles effectively so your body knows to consume fat rather than muscle tissue, youl be ok.

on a cut you are not going to gain any muscle so doing complicated routines/exercises is pointless,IMO do the same routine/weight you are doing for a bulk but drop the isos.

Fundamentally if you want to keep muscle and not get huge but cut it comes down to a diet thing. You have to experiment with calorie intake. Think of it like this... when you bulk you eat a ton... when you slim down you cut the calories... so you have to find a calorie level that is either right at what you burn or just below.

It will be impossible to put on tons of muscle and fat. It will be impossible to loss tons of muscle and fat because you are still feeding the muscle.

Training styles definitely play a role, but I am a little different because I think split routines are waste... unless you are a pro bodybuilder. But I would keep my training mostly in the endurance training mode... more reps and less sets.