Technical Ford 9" is one easier to keep from leaking?

Absolutely. Notice that the seals and the bearing retainer ring look the same and should measure the same.

 

Your question about if that Daytona pinion support it correct for the job. My answer is yes, as long as you ask them for the correct bearing combo and pinion seal for it to work.
Your differential carrier bearings vary by ID and OD based on which carrier housing and which differential assembly. Yours should use the 3.062 OD carrier bearings. Then, you just match the cone to the race part number by using a bearing spec catalog. If it was a straight forward rebuild on the carrier assembly, the bearing kit number would be RA313MK. Custom parts variables may change this answer a lot.
Back to your housing and the axles that lead you to believe they don't match...... One of the bearing races stuck in the housing when you pulled the axles. Back to what I stated before on removal, clean the ID of the bearing race enough to make an inch or so long weld bead inside the bearing race and let it cool. The stuck race should almost fall out. Make it easy on yourself.
Trust me, there are many guys here that have done this job more times than I have and can give advice where I fall short. Let us help you! For y'all that are reading this and want to fill in my gaps, please do!

 

I trust what you and everyone are saying. I'll probably end up getting a strange engineering kit since 1) they make the Dayton support 2) have a full rebuild kit for my diff bearing, solid shim, bearing for the Daytona support. They are all Timken bearings to.

Found a local shop that has a truing jig to make sure the housing is straight. Working on getting the cab blasted first and getting the engine pay for and delivered.

 

Sounds like you're on the right track already. Have fun while building!