I'm certainly going to pat your hand and say that I can tell from your posts that you are indeed an angel
I too have a very opinionated, hard work, strong willed four year old who has had some humungous tantrums so I fully, fully understand how hard things are for you at the moment. I wonder if some of his frustrations are compounded now that ds2 is much more mobile, demanding and attention grabbing; it's a bit easier to cling on to your pole position when number two spends alot of the day immobile/eating/sleeping perhaps? And again, possibly compounded by his having to be at pre-school while ds2 has mummy at home? Not that I'm saying you should change this, of course you need that time when he's at pre-school, just wondering if it has an effect on his behaviour?
He does sound as if he has sensory 'ishoos' but I have heard of many children who DON'T have special needs, who have these things...he sounds pretty normal to me.
Do you play up to his competitive side with things like racing him to get clothes on; or if he plays at being characters you can make his shoes an integral part of the game - though I imagine you will have tried this stuff. I think it's just a case of repeating yourself about stuff like shoes etc, until he comes out of this phase basically.
I'm sure the testosterone surge they get at around four could be playing a part in the vehemence with which he feels everything right now.
So without being glib and saying 'it's just a phase' I'd say remember that this is just a phase My ds was really similar to how you describe yours, he's not five till August but he is I'd say 75% more a reasonable and reasoning human being. No more tantrums........