Your software hopefully includes some kind of "disposition worksheet" or something else with a similar name, and, once completed, it should create the required IRS forms automatically.

They’re disposition specialists and help tons of wholesalers in their markets get their deals sold.

What I'm doing to disposition them right now is:1.

Regarding fees, there are three buckets of fees that investors should be aware of. 1) Upfront Fees - these include but are not limited to acquisition fees paid to the DST sponsor/syndicator, commissions paid to the broker/advisor representing the investor, and other marketing costs associated with packaging and marketing the DST investment 2) Operating Fees - property management fees, asset management fees, and fees paid to the master tenant 3) Disposition Fees - the brokerage fee paid to the sponsor when the property is sold. 

No disposition/capital transaction fee.

I'm thinking if one were to simply drop out of a 5 year investment in year 4 without seeing a disposition (but having initial investment returned), perhaps the COC could be a little higher than the IRR because the IRR would be signaling that five years is a long time to get a return of capital...

When accounting for the disposition of the asset on your taxes, you claim the depreciation as 20K (the amount you should have, but did not originally take), and at the same time claim 10K as an expense on Schedule E, so that your overall losses on the property truly match the amount of depreciation being assessed against the property.  

I have not done one yet myself but my understanding is they lock you in for 5-7 years on average with spelled out expected returns and at the end there is a disposition of the property, trust is dissolved and you'll need to 1031 again to avoid gains tax.

If you believe that you can establish to the satisfaction of the IRS that tax avoidance was not a principal purpose of both the exchange and the disposition, then go for it.

It's important to note that other wholesalers are more likely to JV with you and take a disposition fee rather than simply give or sell you their list.If you're interested in purchasing access to cash buyers, you might consider platforms like InvestorLift, which can cost $25-30K a year for their dispo services.