I want to make the pattern in Investment casting of the component. The Component material is Brass. The component is machined from inside only. No machining is outside.
I'd start by removing the thread features. Those need to be machined into the cast part. You might also reduce the size of the holes that will be threaded. I'd check with the machine shop and see what they want left for material, but boring the part before threading would obtain the best results at the expense of another operation. Even Cut-Extrude5 and 6 could be removed, as they should be drilled into the casting.
I'd then speak with the foundry that will cast the part and learn what they use as a shrink factor for brass in the X, Y, and Z axes. Once you have that information, you can use Insert - Feature - Scale to "grow" the part. Brass can shrink 1-5% depending on the alloy and process used, so speaking to the foundry to get their suggestion is important.
I'd place fillets around the sharp corners of the part where Boss-Extrude9 intersects Cut-Revolve2