Art

No. Scalpel and utility knives work well on thinner leather and the blades are dirt cheap. I've used clicker knives and head knives for years, and they hand sharpen easily.

Yes you (well at least I) can sharpen them. I have a special chuck ($300 long ago) that holds the blade which I apply to a spinning flat hone. The blade spins and the stone spins. Tungsten/Titanium coated blades are not a problem as I use diamond abrasives; it takes the coatings right off.

This can be as easy as making two end pieces and maybe a shoulder pad. You could possibly get by without any work to the belt at all.

Welts and bottoms on bags is where the post shines.

Get a cylinder bed machine, preferably one with a flat table insert. The post machine is seldom a requirement (although that one time you need one, nothing else will do). I do have a post, but wouldn't want one as my only machine. You can do a lot (almost anything) with a post, but it won't be as comfortable as it will be with a cylinder bed.

No, I do not. Bob has never been unfair with pricing. You get what you pay for.

For big heavy leathers, I prefer Bob Beard's edgers. For everything else, I use Ron's.

You want the 16x2. Here's a list of needles you may want to consider from the thread exchange. https://www.thethreadexchange.com/miva/merchant.mvc?Screen=SRCHFA&Search=16x2

For size 33 (commercial) thread like I use on boot tops, I use a size 14 needle, but anything from 12 to 15 might work.

You want 16x2 or DBx2 for that machine. That number is called the "system". Then you need to pick size (generally the diameter of the needle) based on the thread you are using.

Try going up one needle size. Art

These are often called Martengale Hearts.

Well, you certainly made that clear in your original post. Lay part on a piece of grid or graph paper, both sides to be clearer. Now, call OTB and see if they can source what you need. They might not have it, but they can point you in the right direction. These can also be custom made. There are a lot of vendors out there, it might take a few hours on the phone to get a lead. Also, go to your original supplier and ask where they sourced them.

Fact of leather life here. Robert Beard tools sell for more than you paid for them when new. This is on eBay. They seldom come up unless someone dies. Barry King tools can be a little more flexible on price, but they hold their value too.