Here is the full Walk-through for Assassin 56V2. A very, very difficult puzzle with lots of contradiction moves and extensive combination conflicts. Had to restart many times to get a valid solution. Must have spent 15 hours on this one

. Perfect for a V2. Thanks again Para.
Please let me know of any corrections or clarifications needed. The original steps 1-16 have been revised for clarity.
Cheers
Ed
Assassin 56 V2
1. 23(3)n7 = {689}: all locked for n7
2. 10(3)n7 = {127/145/235}(no 8,9)
3. "45" n7: r789c3 = 12 = h12(3)n7
3a. = {147/237/345}
4. "45" n36: r4c6 - 6 = r3c7
4a. r4c6 = {789}, r3c7 = {123}
5. "45" n3: r4c8 - 2 = r3c7
5a. r4c8 = {345}
6. 20(3)n2: no 1,2
7. "45" n1: r4c2 + 1 = r3c3
7a. r4c2 = 2..8
8. "45" r123: r4c258 = 12 = h12(3)r4
8a. min. r4c8 = 3 -> max. r4c25 = 9
8b. min. r4c2 = 2 -> max. r4c5 = 7
9. "45" n4: r4c4 + 1 = r4c2
9a. r4c4 = 1..7
10. "45" n6: r4c6 - 4 = r4c8
10a. r4c68 = [73/84/95]
11. h12(3)r4 = {147/246/345}. Others blocked. Here's how.
i. r4c258 = {138}:
blocked since can only be = [813], but including "45" moves for r4c4 (1 less than r4c2 step 9) & r4c6 (4 more than r4c8 step 10) = [87173]: but this means 2 7's r4
ii.{147} = [714] only
iii. {156}:
blocked since can only be [615] but including "45" moves for r4c4 & r4c6 = [65195]: but this means 2 5's r4
iv. {237}:
blocked since both [273/723] require 7 in r4c6 but this means 2 7's r4
v. {246} = [264/624]
vi. {345} = [345/354]. Others are
blocked. [435/453] by 3 required in r4c4; [534/543] by 4 required in r4c4
12. In summary: h12(3) r4 = {147/246/345} = 4{..}
12a. 4 locked for r4
12b. = [714/264/624/345/354]
12c. r4c2 = {2367} -> r3c3 = {3478} (step 7) and r4c4 = {1256}(step 9)
12d. r4c5 = {12456}(no 3,7)
12e. r4c8 = {45} -> r4c6 = {89}(step 10) & r3c7 = {23}(step 5)
13. Hidden-cage in r345c3 & remembering that r789c3 = h12(3)n7 = {147/237/345}
13a. r45c3 "sees" r3c3, r4c2 and r4c4: these 3 are all linked through "45" moves and = [321/432/765/876]
13b. r3c3 + r4c2 + r4c4 = [321]
i. -> r45c3 = 16 = {79}
blocked: r345c3 = [3]{79}: clashes with h12(3)n7
13c. r3c3 + r4c2 + r4c4 = [432]
i. -> r45c3 = 15 = {69} -> r345c3 = [4]{69}
ii............... = 15 = {78}
blocked: r345c3 = [4]{78} but clashes with h12(3)n7
13d. r3c3 + r4c2 + r4c4 = [765]
i.-> r45c3 = 12 = {39}
blocked: r345c3 = [7]{39}: clashes with h12(3)n7
ii............. = 12 = {48}
blocked: r345c3 = [7]{48}: clashes with h12(3)n7
iii............ = 12 = {57}
blocked by 5 in r4c4
13e. r3c3 + r4c2 + r4c4 = [876]
i. -> r45c3 = 11 = {29} -> r345c3 = [8]{29}
ii................= 11 = {38}:
blocked by 8 in r3c3
iii...............= 11 = {47}:
blocked by 7 in r4c2
iv................= 11 = {65}:
blocked by 6 in r4c4
14. In summary: r345c3 = [4]{69}/[8]{29} = 9{..}
14a. 9 must be in r45c3: 9 locked for c3, n4 and 17(3)n4
14b. r45c3 = 9{26}
14c. r4c4 = {26}
14d. r4c2 = {37}
14e. r3c3 = {48}
15. 20(3)n2 = r3c3 + r23c4 = [4]{79}/[8]{39/57} (no 4,6,8 r23c4)
15. = {389/479/578}
16. from step 12b. h12(3)r4 = [714/345/354] = {147/345}
16a. r4c5 = {145}
Continuing on.
17. from step 16: remembering r4c4 is 1 less than r4c2 & r4c6 is 4 more than r4c8
17a. -> r4c456 = [618/249/258]
18. "45" n4: 3 innies = 18 = h18(3)n4 = 9{36/27}
18a. 14(3) n4 = {158/248/257/356} ({167/347} blocked by h18(3)n4)
19. 17(3)n4 = {269}
19a. -> no 2,6,9 r4c1
20. "45" r6: 3 innies r6c456 = 15 = h15(3)r6
20a. = {168/249/357} ({159/258/267/348/456} all blocked by r4c456! step 17a)
Now: moving across to n36 for the same tricks.
21. r3c7 + 6 = r4c6: r4c6 - 4 = r4c8 -> {r45c7} = 10/9
21a. [r3c7 = 2][r4c6 = 8][r4c8 = 4] = [284]
i. -> r45c7 = 10 = {19/37}
21b. [r3c7 = 3][r4c6 = 9][r4c8 = 5] = [395]
i. -> r45c7 = 9 = {18/27}
21c. In summary: r45c7 = {18/19/27/37}(no 456)
21d. 18(3)n5 = {189/279/378}
22. "45" n6: 3 innies = 14 = h14(3)n6 = {149/347/158/257}
Now for lots of combo. crunching.
23. 16(3)n6 = {169/349/367}(no 2,5,8). Others blocked. Here's how.
23a. {178/457}
blocked by h14(3)n6 step 22
23b. {268/259/358}
blocked by 14(3)n4 (step 18a.)
24. 14(3)n4 = {158/248/257}(no 3,6) ({356} blocked by 16(3)n6 step 23.)
25. deleted
26. Generalized X-wing on 2 required in 17(3)n4 (only in r45) & 2's in n6 (only in r45)
26a. -> no 2 elsewhere in r45
27. 13(3)n4 = {148/157/346}
28. "45" r12345: r5c456 = 15 = h15(3)r5 (note: h15(3)r6 shows all the
blocked combinations for 15(3) by r4c456. See step 20a)
28a. r5c456 = {168/357}(no 4,9)
28b. = [1/5,1/7..]
28c. -> no 5 & 7 in r4c1 as 13(3) must be {157}
28d. but r5c12 = {17/15} will clash with h15(3)r5 (step 28b)
28e. no 5,7 r4c1
29. h15(3)r5 = [5/8..](step 28a)
29a. -> from step 17 r4c456 = [618/249](no 5) ([258] blocked by h15(3)r5)
30. 5 in r4 only in n6
30a. 5 locked for n6
31. 13(3)n4:{346} combo is the only combo with 3
31a. -> no 3 r5c12
32. 3 in n4 only in r4
32a. -> 3 locked for r4
Now to n1.
33. 15(3)r2c2 must have 3/7 in r4c2
33a. = {267/357}(no 1,4,8,9) ({348} blocked by 4 required in r3c3 when r4c2 = 3 step 7)
33b. = 7{26/35}
33c. 7 locked for c2
34. "45" n1: 3 innies = 16 = h16(3)
34a. r3c3 + r23c2 = [4]{57}/[8]{26/35}
34b. = {268/358/457}
35. 15(3)r1c2 = {159/168/249/267/357} ({258/348/456} blocked by h16(3)n1 step 34b.)
36. "45" c12: r126c3 = 14 = h14(3)c3 & remembering h12(3)n7 = {147/237/345}(step 3a)
36a. h14(3)c3 = {158/167/356} (no 2,4) ({248} blocked by r3c3; {257/347} blocked by h12(3)n7)
37. "45" c12: r6c3 + 1 = r1c2
37a. r1c2 = {2,6,8,9}
38. 15(3)r1c2 = {159/168/267}(no 3) ({357} blocked by no candidates in r1c2)
39. 3 in c7 only in n7
39a. 3 locked for n7
39b. h12(3)n7 must have 3 = 3{27/45}(no 1)
40. from step 34b. h16(3)n1 = {268/358/457}
40a. ->14(3)n1 = {149/239/347}(no 5,6,8) ({158/248/257/356} blocked by h16(3)n1; {167} blocked by 15(3)r1c2)
41. {346} combo. blocked from 13(3)n4. Here's how.
41a. {346} combo. -> r4c1 = 3 -> 14(3)n1 = {149} -> r5c1 = 6: but {69} r1235c1 clashes with r78c1.
41b. 13(3)n4 = {148/157} (no 3,6) = 1{..}
41c. 1 locked for n4
41d. -> no 2 r1c2 ("45" c12)
42. r4c2 = 3 (hsingle n4)
42a. r4c4 = 2 ("45" n4)
42b. r3c3 = 4 ("45" n1)
43. r23c2 = {57}: both locked for n1 & c2
44. r45c3 = {69}: both locked for c3
45. r12c3 = {18}: both locked for n1 & c3
45a. r1c2 = 6
45b. r6c3 = 5 ("45" c12)
46. 14(3)n1 = {239}: all locked for c1
47. r78c1 = {68}: both locked for c1 & n7
47a. r7c2 = 9
48. r6c2 = 2, r9c1 = 5 (hsingles)
49. 13(3)n4 = [148](only valid combo)
50. r6c1 = 7, r4c58 = [45]
51. r4c6 = 9, r3c7 = 3 ("45" n3,n6)
52. r45c3 = [69]
53. r23c4 = {79}: both locked for n2, c4
54. r23c6 = {56}: both locked for n2,c6
55. 9(3)n2 = {234}: all locked for n2 & r1
56. r23c8 = {16}: both locked for c8 & n3
57. "45" c89: r6c7 - 2 = r1c8
57a. r6c7 = 9, r1c8 = 7
57b. r12c7 = [52]
The rest is naked or last valid combo.