OK, so here is a question we are discussing on the production team.
"Axanar" takes place in 2245, 20 years before TOS (The Enterprise is launched in 2245). We know the Kelvin (2233) is canon. In the "alternate" timeline of JJ verse, we have ships in 2258 that look Kelvin like, but are obviously older than the new Enterprise. So these ships probably were built before 2233, in fact it makes sense that they were.
We at "Axanar" are not bound by any design aesthetic IMHO, but we want to craft one that makes sense in canon. Our interiors will all look like TOS but with changes. So the ships need to look similar to TOS as well as the Kelvin design aesthetic.
Our designs are squarely BETWEEN 2233 and the Kelvin and 2245 and the TOS Enterprise (launched 2245 and so the pinnacle of Starfleet design). I think we are going to go with the ST 09 ships and assume that they are the generation BEFORE the Ares and two generations before Enterprise.
We might even upgrade some of them with Ares style engines.
I would love to hear what people think about this.