Well, at least you have a cake and a plan, so that's a start. The two cakes should give you the height you want. I would try the stock syrup on your test cake to see if that increases the moistness of it. It looks lovely.
When I bake, I try and leave a day for the cakes to rest before I level, fill and cover them, but because we don't know how long this cake will stay fresh, it's up to you. For me, I would bake it Thursday, coat in stock syrup if that works on the cake, let it cool fully and then wrap it in baking paper and clingfilm and allow them to sit. Clingfilm breathes, hence the reason I use baking paper to cover them first.
You can always add a little stock syrup to the cake Friday if it is a touch dry, and the filling and coating will help with the overall flavour. The fondant should then help seal in what moisture there is. I think if you do everything on Friday, you have a lot to contend with. If it was just a simple buttercream exterior coating, then yeah maybe, but seeing as you are covering in fondant, then no, give yourself time to do each stage.