I have a duobt about the number of attacks you can make if you have both feats.
Great cleave says "As a standard action, you can make a single attack at your full base attack bonus against a foe within reach. If you hit, you deal damage normally and can make an additional attack (using your full base attack bonus) against a foe that is adjacent to the previous foe and also within reach. If you hit, you can continue to make attacks against foes adjacent to the previous foe, so long as they are within your reach. You cannot attack an individual foe more than once during this attack action."
https://www.d20pfsrd.com/feats/combat-feats/great-cleave-combat/
So, if i hit goblin A, i can make an aditional attack against goblin B if he's adyacent to gonlin A and within my reach...
But then Cleaving finish says "If you make a melee attack, and your target drops to 0 or fewer hit points as a result of your attack, you can make another melee attack using your highest base attack bonus against another opponent within reach."
https://www.d20pfsrd.com/feats/combat-feats/cleaving-finish-combat
So, if I hit and Kill goblin A, i have two aditional attacks against the poor goblin B, because he's adyacent to goblin A and i also killed goblin A. Am i right or i'm missing something?
If that's right, and i get improved cleaving finish (that let's me do cleaving finish any number of times per round), and let's say i hit and kill goblin A, and following my great cleave i also kill in one shot goblin B, who is adyacent to goblin A and within my reach, then now i have the great cleave attack against a poor underpaid goblin C, who was adyacent to goblin B and within my reach and ¿I still have the two addictional attacks of improved cleaving finish beacuse i killed Goblin A and B?
Example 1:
Lets say you have natural reach 15ft and can hit targets within 5ft, 10ft, and 15ft, and you have Great Cleave and Improved Cleaving Finish, and there are 5 goblins:
45
123
PC
where goblins 1, 2, and 3 are 5ft away from the PC, and goblins 4 and 5 are 15ft from the PC.
It's your turn, and you use a Standard Action to Great Cleave goblins 1, 2, and 3 and all three hits land successfully, and you kill all 3 goblins, which generates a total of 3 free attacks from Improved Cleaving Finish. Because goblins 1, 2, and 3 are now dead, it looks like this:
45
xxx
PC
and since you have 3 remaining attacks and goblins 4 and 5 are still within your threatened range, you may perform all three attacks on goblin 4, or even spread out the attacks by striking goblin 4 twice and goblin 5 once.
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Example 2:
Lets say you have natural reach 15ft and can hit targets within 5ft, 10ft, and 15ft, and you have Great Cleave and Improved Cleaving Finish, and there are 5 goblins:
45
123
PC
where goblins 1, 2, and 3 are 5ft away from the PC, and goblins 4 and 5 are 15ft from the PC, same as the above Example #1.
It's your turn, and you use a Standard Action to Great Cleave goblins 1, 2, and 3 and you successfully hit goblin 1 (but don't kill him) and then hit goblin 2 (and kill him) and then you miss with your Great Cleave's last attack on goblin 3; since you killed goblin 2, this generates 1 free attack from Improved Cleaving Finish. Because goblin 2 is now dead, it looks like this:
45
1x3
PC
and since you have 1 remaining attack from Cleaving Finish and goblins 4 and 5 are still within your threatened range, you may perform this free attack against ANY goblin you wish (because they're all in your threatened range), even though you already struck goblin 1 with your Great Cleave, and even though you missed goblin 3 with your Great Cleave.
Change Gears: In this example #2, let's say you had killed goblin 1 as well as goblin 2, you would generate 2 free attacks from Improved Cleaving Finish, and you would be able to perform both of these two free attacks against ANY goblin you wish (including goblin 3 who you just missed with your Great Cleave), and you may even choose to use both attacks on a single goblin, or spread each attack against separate goblins, if desired.
Example 3:
Lets say you have natural reach 15ft and can hit targets within 5ft, 10ft, and 15ft, and you have Great Cleave and Improved Cleaving Finish, and there are 6 goblins:
45
123
PC
6
where goblins 1, 2, and 3 are 5ft away from the PC, and goblins 4 and 5 are 15ft from the PC, and goblin 6 is 5ft behind you and not adjacent to goblins 1, 2, or 3.
It's your turn, and you use a Standard Action to Great Cleave goblins 1, 2, and 3 and all three hits land successfully, and you kill all 3 goblins, but because goblin 6 is not adjacent to goblin 3, your Great Cleave ends. Since you killed 3 goblins with your Great Cleave, this generates a total of 3 free attacks from Improved Cleaving Finish. Because goblins 1, 2, and 3 are now dead, it looks like this:
45
xxx
PC
6
and since you have 3 remaining attacks and goblins 4, 5, and 6 are still within your threatened range, you may perform all three attacks on goblin 4, or even spread out the attacks by striking goblin 4 twice and goblin 5 once, or even spread out the attacks to hit each remaining goblin once (even though Goblin 6 is "behind you", Pathfinder does not have facing requirements, so you may choose to hit goblin 6 with any one of your 3 attacks generated by Improved Cleaving Finish). Alternatively, you may even choose to perform all three of these attacks against Goblin 6.
Short answer: Yes to everything.
Cleave and Great Cleave both are active abilities, meaning they require spendign an action and can't be used alongside other active abilities requiring the same action. Cleaving Finish, however, is a triggered ability, which don't (usually) require actions, and thus is can be used alongside (and triggered by) Cleave/Great Cleave.