Regional pass - 14 days

We will be spending 14 days in the Sanyo-San'in Northern Kyushu region and will be buying the regional pass.
Do we buy 2 passes each and specify the dates so they run consecutively? How will this work as it's not clear on the website?
We will also travel to southern parts of Kyushu but as far as I can see, the cost of a trip to Chiran and possibly other local areas is not worth purchasing a national rail pass.

Do we buy 2 passes each and specify the dates so they run consecutively? How will this work as it's not clear on the website?

Yes, you can buy 2 or more passes unless they overlapped the dates. But you can also consider other combination of transportation.

Kansai area to Kyushu is connected with airlines which are in general cheaper than trains. I am a resident of Kagoshima and Kagoshima to Kobe/Itami/Kansai is from 4000 yen to 10000 yen by air. So I always choose to fly to Kansai area.

One candidate combination is:

Fly to Kagoshima (8000 yen)

See Skymark, Peach, ANA and JAL websites and find suitable flight.

All Kyushu Area pass

https://www.jrkyushu.co.jp/english/railpass/railpass.html

7 days 25000 yen

Sanyo-San’in Northern Kyushu pass

7 days 26000 yen

Total: 8000 + 25000 + 26000 = 59000 yen

You can buy 2 (or more) passes as long as the dates don't overlap. However, just because you're there for 14 days doesn't mean you automatically need 14 days of rail passes. Some days you might not travel very far, if at all! The Kyushu pass has different versions and day limits, so you can combine them depending upon your actual itinerary and travel needs. If you post your actual travel plans here, people will be able to advise the most cost effective way of getting around.

Thanks for the suggestions.
We are not travelling until May next year so have a bit of time to plan.
I thought I might post my wish list and see what suggestions come up for best places to visit and travel options.
We fly into Kansai Airport and have 17 days of travel.
2 days of walking the Kumano Kodo track is first up.
Some areas we are considering are Himeji, Onomichi, Kurashiki, Izumo-Matsue (may not have enough time), Fukuoka, Nagasaki, Takachiho Gorge, Chiran.
We would also like to spend a couple of days in Shikoku and spend another day (or 2) riding the Shimanami Kaido.
What about flying to Kagoshima from Osaka after Kumano Kodo and travelling around on the All Kyushu Area Pass. Then a 3 day Shikoku Pass and maybe a 7 day pass to travel around the southern coast of Chugoku (or buy tickets as required).
Any tips of best places to visit in these areas and transport options would be much appreciated!

You may also consider Setouchi area pass, 7 days 22000 yen.

https://www.westjr.co.jp/global/en/ticket/pass/setouchi/

This pass includes JR Shikokus northern Shikoku lines from Iyo-Ozu (nice small town) to Ritsurin (famous park) and high-speed boat from Hiroshima to Matsuyama (normal fare is 8000 yen).

In any case you have plenty of time to plan. Enjoy planning!

What about flying to Kagoshima from Osaka after Kumano Kodo

Probably you will come back from Kumano Kodo via Wakayama or Koyasan so Kansai Airport is convenient. From Kansai airport to Kagoshima you will take Peach Aviation, which is an LCC so that you can find lowest fare (maybe 5000 to 7000 yen depending on the date). Luggage is restricted to 7 kg so you may need to pay extra foy your big lugage (1590 yen per luggage, which is quite fine price: slightly cheaper than the luggage transfer service in Japan). In the past you can choose the front row seat (spacious leg room) even from the lowest price, but now it is allowed only when you book the pricest plan.

Thank you! That looks like a perfect option for us.
Followed by an All Kyushu Pass and fly back to Osaka.
Many thanks for your help.