Not true at all Indiana does have conferences. In fact the leadership of the SWOC tried to merge with the EIAC (Eastern Indiana Athletic Conference) a few years back. East Central, Lawrenceburg, Batesville, Greensburg, South Dearborn, Franklin County, Rushville, and Connersville. Harrison would fit well into this league with travel not being as far as if they were to join the ECC or GMC.
and before you ask, no there are no rules preventing intra-state conferences
The SWOC falling apart intrigues me.
If the leagues stays together you have a four team league, and you basically have another GCL-S with only 3 league games.
Northwest and Mt Healthy easily go to CMAC and are happy there. The schools are similar and they would be a good fit.
Talawanda and Harrison are left out.
Talawanda could join the SWBL in round two. I am hearing some of the smaller schools in SWBL might mover over to the Southern Buckeye Conference freeing up room in the SWBL.
When the FAVC broke up and became the SWOC and ECC they did it because of massive travel. So I don't see Harrison going to the ECC. Harrison is too small for the GMC and the GMC is happy with 10 teams right now, I don't see them wanting 11. The CHL is another option, but they might be too big for them. The CMAC verfy different demographics and wouldn't be a good fit. These are the only Hamilton County/Butler County Conferences I know of.
I do like your idea of joining the Indiana Conference. The schools you listed very greatly in size ( I am not an expert on their size) So they would fit. They could join the conference and no rules are against it. I have heard of Ohio/Michigan and Ohio/West Virginia conferences. The problem I see that could be a potential is too many teams already in the conference. You listed 8 schools. Indiana only plays 9 games. So if Harrison were to join, that would mean the Indiana schools would only have one non-conference game, Do those schools like that? For instance East Central and Harrison always play anyway, does East Central have another game like that, it wouldn't be able to play because of the expanded conference? The second point is that Indiana and Ohio don't always start football the same week. Indiana for the longest time always started a week earlier than Ohio, that could mess somethings up for football. The other thing is are the sports offered at the same time? In Ohio Boys Tennis is a Spring sport, Indiana it is a fall sport.
Personally I would love it if Harrison and to a lesser extent Talawanda would be forced to go Independent. This would almost force a dream match up for me of Elder vs Harrison. If you think about it when Winton Woods was forced to go independent, that is when they started to get good. They were playing better teams that forced them to get better.
On the flip side The SWOC has only had 6 members and 5 leagues games so members are use to finding 5 other games. The four schools could stay together and just find 7 games.