The only effortless way that I see in placing your seal at the blade is by using electro-etching, which for you will be a simple issue since you have the logo and with photoshop you can reduce it to 2/3 of the blade width. This, as you know will save a lot of time. Carving is troublesome and takes a lot of work out of you. Meantime I must stress that you don't feel obliged to either electro etch or carve the seal, my friend, but just in case you insist, I placed the position for you reference. Please note that the Mune is on top and the cutting edge is bellow. I'd need the blade with me around the 18 of July as I'm living on the 20th. and will want to have a wooden box made.

I think this Wood branches Tsuba could be renovated by receiving not a blueing solution, but in hope that it is steel and not shakudo, it could be blackened with Black Oxide and the golden parts receiving a silver plating.
Fred Lohman uses Black Oxide process to blacken and give a semi-gloss finish and perhaps you could coordinate with him to do the job. It only works with iron tsubas. What other alternatives are there to attain the final look on the right image? It could go for the Katsujin-ken.Black with a touch of silver...