England is not that big, and it took centuries to unify anyway, so it's not some sort of unlikely scenario.
I don't get why Iberia would join the Ottoman empire at all, especially with a 18th century POD, makes no sense. The rest should be possible, although you have the Ottomans just overthrow centuries of trade routes building and colonial empires in a single swoop, which seems also unlikely at best.
17th century, and Spain's disasters all happened offscreen. I wouldn't look too hard into the details, it was a fifteen minute rushjob that left most things to allusion, as well as the amount of time over which things happened. That said, if the Ottomans did turn their full attention onto the Indian Ocean then yeah, they could definitely disrupt many trade routes via conquering or usurping trade posts to local powers considering how far away Europe is and the amount of time voyages took.