Starter safety circuit

My 1 year old solenoid may be the thing that keeps my starter circuit from working, or it could be one of the safety switches between the key and the solenoid.
AFAIK there is a plastic plunger on the engage/disengage rod that closes when the blades are dis-engaged.
There is also a snap switch under the seat that closes when there is weight on the seat.
I don't think I have any switch on the clutch and definitely have no neutral switch.
I bought a safety lanyard switch that I didn't install yet.
I am wondering which of these things I don't need, if any, or is there something more I should add?
I'm also thinking a beeper wired to the solenoid input would tell me if turning the key actually caused power to reach the solenoid terminal.
Any thoughts?
I plan to have the mower deck on it sometimes, or a snow blower, or what-ever.

I know when I have an issue like that I typically bust out the multimeter and test, starting at the solenoid going backward from there.  Which direction doesn't matter, I do it that way to rule out the solenoid itself first.

The solenoid bypass test (a.k.a. screwdriver shorting the solenoid output studs together) made the starter work. My question is really more about the ultimate set up for the tractor, not so much diagnosing a problem. I'm going to be just as lazy next time there is a problem, as just as reluctant to fork over $50+ for a solenoid when one is needed again.
The solenoid coil signal must run through the seat switch, the disengage switch, and the key switch (that part I did myself). I'm not sure how much weight is needed on the seat to close the seat switch. Half a patio block is about 17 pounds, enough to hold my clutch when installing a belt but maybe not much compared to my 250# rated backside. Pulling connectors to test circuits violates the principle of not messing up stuff that isn't definitely broken As I recall there are 2 safety switches under the hood too, maybe the clutch does have one too.
If I was truly nerdy I would run sense lines to LEDs that would tell me what has juice and what doesn't.
I'm also thinking about swapping the solenoid for a high amp starter switch. I think I saw one at Pep Boys. That option would void the safety switches unless I put them in the run circuit. Then bouncing off the seat would cause a shut down but there would be no temptation to leave the mower running while getting off to do something.
Of course we can't have the mower engagement status affecting the engine running status.
That's why I am asking if the safety switches on the starter are really necessary given that it could be pull started any time it would keep running if it were already ready running.

I am not the biggest fan of safety switches. I have zero on my wheel horse I mow with. after a rollover incident with old red I did install a safety lanyard which is a pretty good set up because it’s easy to pull if there’s a problem or if you fall off. On a lot of tractors The starter cell annoyed circuit goes through the the clutch safety switch. to keep you from inadvertently starting the tractor and gear which is a good idea. Then the kill wire goes through the seat switch and kills the tractor if the PTO is engaged and you get off the tractor which is another good idea.