Load Bearing Wall- Beam or Post?

I have an L-shaped wall in my kitchen which I'd like to remove to open the area up to the living area. The wall is obviously load bearing - it supports a ceiling joist hanging beam which spans the length of the kitchen (4.24m) and the other part of the L-wall (which is only about 2m) also props up a roof beam.

Ideally I would like to get rid of the wall completely which I imagine a builder/structural engineer would be able to do with beams, but I imagine it will get pretty complicated and expensive? (Not to mention that I then have another problem - a flush continuous ceiling between the two existing rooms, with two different types of cornice to deal with!

So with that in mind I also have a visual plan in my head for a kitchen layout that embraces a post where the corner of the L-shaped wall would have been because I figure this might be a simpler option?

This is where my questions start. Is it in fact any simpler or cost effective to do with a post than to do with beams above the ceiling?

If the wall were to be removed the existing bottom plates would have to be removed therefore eliminating the distribution of the loading on that post through to the bearers? Does a post have to be directly above a stump to transfer its load through to the ground or can it be anywhere along a bearer? - I'm just trying to get an idea of whether a post will have to be in exactly the same position as the existing corner or if it can be moved.

The corner of the current wall is a three studded corner, and both parts of the wall are diagonally braced. If the wall were to be removed and therefore the diagonal bracing and noggings, what gives the post support laterally?

And subsequently what then gives the two new corners (or wall ends) there lateral support? Do they then have to become three studded end posts so that they dont bow out?

And finally, since the top plates of each part of the wall being removed become the load bearing beams do they get completely replaced or would you fit appropriately sized beams underneath them to support them? This might mean there will be exposed beams below my ceiling, but this might be ok bceause it could be a way of changing between my two types of cornice!

I realise thats a fair few questions in one post. Any words of wisdom on any of them will be much appreciated.