Gentlemen, all of those methods might get you to step 1, but cannot assure you of successful certification of coordination.
I need to ask, is this for a business or public safety system? The methods used in determining a frequency are significantly different.
A business coordinator will place non-exclusive (non-FB8) systems with overlapping coverage and use the "shared use spectrum" clause of 90.175 to justify the action. As such, it is the licensees' responsibility to monitor before transmitting and share the frequency. Some technologies (like mixing legacy analog use with new TDMA [DMR, etc.] digital) don't play well with the sharing concept. Your frequency WILL have someone else on it. If you listen, you might be able to pick one or two that are relatively light. I know some oldtimers in the business who used to put up a receiver on a site with a community repeater tone panel, then display the number of tones used and the transmission duration time. Then they'd apply for the frequency that had the least amounts of airtime and tone hits.
A public safety coordinator will use R-6602 contours - for UHF - the proposed's 21 dBu F(50,10) "interference contour" vs incumbents' 39 dBu F(50,50) "service contour." If they intersect, the coordinator will require the proposed system to get a "letter of concurrence" from the incumbents. The smaller the footprint, or the more contained the antenna pattern, the better the chances of being approved with minimal difficulty. This doesn't always sink in at the manufacturer or service shop level.
The problem may be that incumbent systems are built to excess. A 1 square mile town building countywide coverage, for example, or the biggest antenna on the highest location using the highest power. Another problem is warehousing of spectrum. A secondary channel that's used once every two or three years might be a good example of that. STILL, it's protected and there's nothing currently that can be done about it. These frequencies will pass your scanner monitoring tests, but will fail frequency coordinator methodology.
A coordinator will "have to" give you something. For public safety, it's still something that might require action on behalf of the applicant (sometimes by requirement of the coordinator, sometimes by requirement of rule) to provide some sort of action to get it. Usually that is 90 days to follow a certain process of either getting a response, or producing certificate of service within a given time frame. After that, you start over.
One word of advice (free advice is always worth what it costs) - never put something on the air without at least securing a Special Temporary Authorization from the FCC. Yes, you "can" do it, and you "might" get away with it, and "probably" nothing will happen. The industry is largely self-policing, and when the Commission does respond to an interference complaint from an unlicensed source, it tends to look at the action as a potential revenue source. An ATM. An industry newsletter recently reported that the FCC had assessed $294,400 against Constellium Rolled Products Ravenswood, LLC for operating on expired licenses. There are other reports of various enforcement actions. Unlicensed operation (even expired license operation) usually requires a pretty good deal of committed resource to find and might be a little like poking a hibernating bear with a stick. Maybe it won't wake up, and maybe you can run faster than it can. Maybe not.