Actually I consider it also something like bluffing with the best hand.
You're a clever guy, don't say things like this. You can call it betting for info or, if you want to sound clever rather than a donk, range manipulation, but you can't bluff with the best hand on the river.

Here's your EV calculation with your own assumptions. I took the middle ground of 60% spade, 35% air:

Option 1 (c/f): 0
Option 2 (c/c): +$0.30
Option 3 (shove): -$6.70
Option 4 (b/f): +$3.05

Unsurprisingly, your option of b/f has come out on top. I say unsurprisingly because you set up all the numbers to be perfect for that line. Let's look at some other possible sets of action he could take:

1. Instead of folding all worse hands when you b/f and calling with all his spades, lets say he shoves over with the better half of his spades (so 30% of hands) as well as 10% air. I've deliberately chosen these numbers so that you can't quite call the ship profitably, thus saving us from having to consider b/c as an option. Let's also say that he calls your tiny bet with some non-spade hands; let's say the 5% that beat you +5% that don't. Now the EV of option 4 changes to: +$1

2. Instead of shipping his entire range when you check the river, he checks back some hands that you beat, either because he thinks he has showdown value or because he thinks you'll call his bluff or whatever. Let's say he checks back 1/3 of the time when behind. EV of check/fold now changes to +$2 (c/f as a line can have some value, coming from when you don't have to fold)

3. Let's say he also checks back a lot of smaller spades as well (very likely IMO) and is thus shipping a polarised range on the river. If more than about 35% of this range is air then you can call and raise your ev above the +$2 value given in 2.

4. Perhaps he will bluff with a wide range as you suggest, but will bet smaller than all-in, allowing you to pick the bluffs off more profitably, boosting your c/c EV.

I've tried in these example scenarios to suggest reasonable possibilities, rather than extreme cases. There are worse lines villain could take for your bet/fold line. What if he shoves over with all his spades +20% bluffs? Then your b/f EV goes to -$1.30. Or perhaps he's going to give up a lot more on the river; EV of c/f could go anywhere up to +$6.30.

I think it's important that you see that while your bet/fold line could well be best, you have assigned a very specific set of actions to your opponent that make it the best option. It is super-exploitable and relies heavily on your opponent playing perfectly against your hand if you check, and very badly against it if you bet.