What to do with firehearth and fireplace, cement and tile?

[compact]

Hi
I have opened up a fireplace in the back downstairs room.

I have plasterboarded it and having it skimmed.
I am going to leave it as a hole / feature.

Questions
1) What to do with the hearth. It is full of soot, bricks/stones etc.
I was thinking dig out as much as I can. Hopefully not hitting soil and then cement. Can I cement onto soil? It will only be a foot squared.
Any other ideas? (ps never done any cementing before)

2) The small area infront has broken tiles, on top of broken tiles. We are going to take up the carpet and have bare floorboards, so are thinking of removing all tiles and re-tiling it. Any ideas of nice 'authentic' but cheapish ones to use?

3) Would you continue the tiles into the hearth onto the newly cemented base?

4) I have not boarded the top hole up the chimney yet. I don't know it is has been caped, still has chimney pot etc. Can i just put a piece of plasterboard across the top. Do I have to put holes in it? (this could let soot fall through?) Should I paint or treat the board in case is gets a bit damp? Should I use wood instead of plasterboard?

All advice welcome.

Here is a photo of it as it is, hopefully it sheds a little more light on the situation.

 

[Bahco]

Can I cement onto soil? It will only be a foot squared.

Put a bit of hard core down and cement it level.

Any ideas of nice 'authentic' but cheapish ones to use?

Look in the clearance section of tile shops.

Would you continue the tiles into the hearth onto the newly cemented base?

Look naff if you don't.

Plasterboard or wood will be ok to block the chimney if it is no longer in use.