Too few details to answer (Of course this varies county by county, all questions could be answered by reading the (zoning)/building code and/or clarified with a visit to the county planning office).
but some clarifications because: lots of things are "tiny homes" but what you describe small houses "on permanent foundations" needs to be clarified , tiny homes could be:
-stick built, see below. check your county code/planning dept
-stick built cabins/recreational, a specific zoning and potential occupancy/etc restrictions but worth looking into where the zoning allows for it
-hud manufactured homes (smaller singlewide perhaps 400sq ft 600sq ft minimum)
-non-hud park models (on axles), ansi standards
- other "RV's" built on a chassis: organizations, state agencies, etc - will certify factory built (or sometimes inspected professional built) tiny homes on chassis - to whatever standards ansi, riva, dot/ l&i?, code. Often a grey area or banned for full time occupancy, though.
OP- Please feel free to come back ad post an update on what you've found.
Development costs will often be the biggest hurdle, meaning: sell the land you have and buy an existing park, campground, rv park and "upgrade"/ convert the sites to tiny home compatible. - and you'd be ahead.
-"commercial" local/regional tiny house builders will offer some financing option or another, find someone local in your price bracket and work with their financing
-park models can be financed through dealers/(etc), and small ~400 or 600 sq ft singlewides, although getting spendy, perhaps, could look attractive once you factor in the negative of anything smaller being tough or impossible to conventionally loan down the line. Owners who buy in get that new home feel anyway.
-so what you could try for financing on anything less conventional- package the land lease and the factory built tiny home, and approach your local credit union until you find a combination that works.
Anyway you should also read up on co housing, co-ops, (yes condos) and other clustered developments as they apply to your county codes. The code will often have provisions for clustering development while leaving other natural areas of the development open space/etc. Many ways that pans out but overall "condo model" in terms of what you're describing, either way. Co-housing communities are currently more "mainstream accepted" especially financing-wise. In some areas code will allow you to increase the overall density, significantly, and whether you build individual stick tiny homes or connected condos/multifamily, still a model to follow for streamlining your financing/package. And perhaps streamlining permitting/etc a bit. All the cohousing developments I've come across have a high degree of pride of ownership and community. Too much so honestly, (they aren't typically affordable). Many local groups will step in to find and fund "first time etc" qualified hard working homeowners though, find great tennants to get in your units if you go this route, & set it up correctly.
If states like Indiana are pushing that they are "tiny home friendly" (in that case I've heard of the log cabin law, but don't necessarily know if that's directly applicable to community-scale developments). I'd like to see how it turns out overall for builders & developers who do go that route, and if the county streamlines/encourages the process at all. Compare the all-in $'s to putting in a 14x40 single wide, basically. or barebones duplexes/conventional attached development... It would be great if progressive views/laws on reducing minimum square footage (residential/single family on foundation) were indeed the case in Indiana, and will to catch on (re-evaluating minimum size of homes) elsewhere.