In a nutshell, yes they are all backward compatible. They are all detergent based- all have EP additives, anti oxidants and acid control- and are all 4 stroke oils. But we are talking about a very specific application here i.e. ZDDP for flat tappet engines.
Thing is, nothing protects cam lobes like good old ZDDP that forms a layer there to protect it against extreme flash temperatures. Only reason to drop ZDDP quantities in newer oils is that the Phosphorus clogs CAT cons. It's not like they've found a better EP additive to replace ZDDP.
Now your motor not only employs flat tappet but also a variable cam lift and valve duration. It's specifically needs lots of ZDDP to protect it, it's been designed to use it. If it were okay with reduced why'd Honda go into the trouble of making new roller rockers for iVTEC motors?
Now, you don't have a CAT con or O2 in your exhaust, so what's your worry? And your motor might just, just, do okayish with newer oils, bearing some cam lobe wear or premature failure- but it'd definitely better with older one. So why waste money on something that is not required or recommended- or is even debatable.
As for the part of baseless arguments and all that, I tried to tell someone in an other thread that arguments are good, they bring knowledge and vision- especially when they're coming from a fellow who has some experience of sorts. Try asking @Xulfiqar for instance. But you, my friend don't take it personally, hardly sound like a fellow who has much experience of cars or motors.
Oh well at the end of the day it's your motor- and not a very expensive or rare one- so it's your decision. I wouldn't put any SN ZIC or KIXX in my vtec motor anyway.