Solution to 18D has been deliberately left unsolved and is to be answered only by a non-regular / novice commenter, with proper annotation. Those who have answered earlier in the week, please give others a chance.
ACROSS
10 Kills abilities of employees? (8) SKILLSET {KILLS}* [RA]
11 Memorised books on Shakespearean character (6) LEARNT {LEAR}{NT}
12 Injected botox, say to cover one having feet down (8) PLUMIPED {PLUM{1}PED}
13 American retracts final word without single condition (6) ANEMIA {A}{A{1}MEN<=}
14 Top post initially grabbed by evil person (7) SPINNER {S{Post}INNER}
17 He doesn’t believe a bank job consumes time (7) ATHEIST {A}{T}{HEIST}
22 Check others in front of shower (8) RESTRAIN {REST}{RAIN}
25 Jumped and spilt the beans without press reports initially (6) SPRANG {S{Press}{Re...s}ANG}
26 Fast track income from marijuana according to Spooner (8) SPEEDWAY (~weeds pay to speed way)
27 Frequently recalled diet that could be cultivated (8) EDUCATED {DiEt+ThAt+CoUlD+bE}<=
28 Deal with fishing gear (6) TACKLE [DD]
DOWN
1 Friendly gesture of pals (8) BACKSLAP {PALS}<=
2 Small cracks around circle in obstacle race (6) SLALOM {SLAL{O}M*}
3 Exhausts America with drugs and drink (4,2) USES UP {US}{E}{SUP}
4 Keeping scout busy on vacation day (7) CUSTODY {SCOUT*}{DaY}
5 Holy man wielding Indian sword is sturdy (8) STALWART {S{TALWAR}T}
6 Tongue has same sensation inside (8) ASSAMESE [T]
7 Henry drills to fix unit in plant (6) MEHNDI {ME{H}ND}{1}
18 Fit sailor touching 50 occupying rooms (8) S?I?A?L? (Addendum - SUITABLE {SUIT{AB}{L}E} - See comments)
19 Spider crawling on engineer’s chair (7) PRESIDE {SPIDER*}{E}
21 Walked unsteadily leaving top English bar (6) IMPEDE {lIMPED}{E}
23 This elegant actor and author writes plays — creates “Oliver Twist” (6) SVELTE {SVELTE+ACTOR+I+WRITES = CREATES+OLIVER+TWIST} [CA]
24 Friend’s uncle regularly supplies contract (6) REDUCE {fRiEnDs+UnClE}
Reference List
Boy = B, Europe = E, Books = NT(New Testament), American = A, Time = T, Drugs = E, Holy Man = ST, Indian sword = TALWAR, Henry = H, Sailor = AB, 50 = L, Engineer = E, English = E