Captain Paul Danson had called on both to seize their opportunity in the senior side this season and they did just that on day one at Stanley Park.
Lewin took 3-36 from his 12 overs and Henshall 3-24 from eight as Leyland were restricted to 194-9 from their 50 overs after being asked to bat.
There was a third three-wicket haul from a familiar source, Matthew Grindley taking 3-58 from 15 overs as opener Jacob Wright held the Leyland innings together with 73, including 10 fours, before falling to Lewin.
Andrew Makinson contributed 37 but that was only one fewer than the six men who followed him in could managed combined.
Danson had tipped Leyland as one of Blackpool's strongest challengers this season but Tomas King set about pursuing the target with gusto, scoring 89 from just 71 balls as 70 of his runs came in boundaries (16 fours and a six).
Henshall completed his fine day with 57 (10 fours) batting number three as Blackpool sealed victory with eight overs to spare at 195-6.
Blackpool were without professional Naushad Shaikh and could not engage a sub-pro either while waiting for the Indian's visa documentation to come through.
St Annes also made a fine start with a 10-wicket victory away to promoted Palace Shield champions Penrith.
Tom Higson has passed the captaincy baton this season to focus on his performances with bat and ball and that paid immediate dividends as the opener's 80 from 42 balls (also 16 fours and a six) enabled St Annes to seal victory in Cumbria in just 15.3 overs.
Higson shared the unbroken stand of 115 with Luke Jardine, who was unbeaten on 26 when the 15 points were sealed.
All-rounder Higson had earlier starred with the ball too, taking 4-31 from 12 overs as the hosts were dismissed for 112 in 43.3 overs.
Put in to bat, Penrith slumped from 43-1 to 49-5 and couldn't recover, with only James Bowman (29) reaching 20.
The other four NPCL games saw newcomers Vernon Carus (95) lose by 80 runs at Chorley (175-5), while Garstang (185-4) defeated Netherfield (184-9) by six wickets and Kendal(152-7) got the better of Fulwood and Broughton (119) by 33 runs. Other than St Annes, the only away winners were Longridge (217), who triumphed by 121 runs at Lancaster (96).
Lytham began their Liverpool Competition season at the Lancashire outground of Aigburth and defeated Liverpool by six wickets.
The hosts regretted their decision to bat as they were dismissed for 95 in 37 overs in this division one opener.
Former Lancashire player Toby Lester marked his return to the Lytham ranks with 3-35 from 11 overs, while Thomas Hessey contributed 3-23 from 10. There were two apiece from Josh Holden and Richard Openshaw.
Jared Clein's three quick wickets then raised home hopes of making a match of it as Lytham were reduced to 46-4.
But Liverpool enjoyed no further success as Holden and wicketkeeper Richard Staines shared an unbeaten stand of 51 to see Lytham home in 29.5 overs.
Holden contributed 38 from 57 balls (six boundaries) and Staines 20.
Fleetwood started their first season in the Palace Shield after 70 years of Northern League cricket with a 12-run victory at Eccleston which had looked unlikely.
The visitors chose to bat put had stuttered to 78-8 before new overseas amateur Zac Corcoran made a late 40 to propel the total to 155 from 43.3 overs.
Only two of the eight in before him reached double figures as Reece Thomas took 5-54 from 15 overs.
Australian Corcoran found a willing ally in number 10 Jack Wilkinson (23) in a ninth-wicket stand of 57.
Corcoran then starred with the ball too, claiming 4-30 from 8.3 overs as Eccleston fell short at 143 all out from 40.3 overs.
The hosts looked set to reach their target at 79-1, wicketkeeper Adam Norris making 35, but this soon became 100-6 and their momentum was lost.
Also in the premier division, Kirkham and Wesham went down by 29 runs chasing impressive visitors Barrow's 227-8.
Nicholas Elliot (77) and Christopher D'Leny (61) showed why the Cumbrians chose to bat, though Jamie Hogarth responded to the challenge with 5-44 from 11 overs.
K&W opener Stephen Wright wasn't daunted by the chase but after he fell for 76 (11 boundaries) at 170-6, the tail fell cheaply and defeat was confirmed at 198 from 42.1 overs as Sam Henderson took 4-36.
The first Fylde coast derby of the season went the way of Thornton Cleveleys, beating visitors Great Eccleston by 31 runs.
Jon Eade and Josh Sackfield both scored 56 in a total of 201-5 after TC had been put in, Jim Proctor taking 3-48.
Ecc then lost their top three for a combined total of two before Alexander Rhodes (47) and William Turnbull (37 not out) gave them hope.
But the last wicket fell at 170 with 2.3 overs remaining as Jordan Beech took 3-23 from eight overs.
Elsewhere, Fleetwood's fellow relegated club Morecambe piled on 230-4 to beat Preston (144) by 86 runs, while Torrisholme (165-8) beat Euxton (139) by 26 runs and Croston (98-1) cantered home by nine wickets after dismissing hosts Penwortham for 94.
Fylde (163/9) lost by eight wickets at Carnforth (167-2) in division one despite Dan Smith's unbeaten 69 as the home openers then put on 115.
Wrea Green (186-6) won by 93 runs at Preston 2 (142-8) in division two with Jack Jones unbeaten on 51, while Norcross (146-5) were winners by four runs at St Annes 2 (142-8), half-centuries for Norcross from Michael Griffiths (58no) and Iain Green (57).
Blackpool completed a three-match opening weekend with a Readers T20 double-header at Stanley Park on Sunday.
Their first two group games saw a 21-run victory over Leyland followed by an eight-wicket defeat by Chorley.
Wicketkeeper Ben Howarth captained Blackpool and led from the front as the hosts beat Leyland for the second successive day.
Put in to bat, Howarth scored 43 from 38 deliveries in Blackpool's 111-6, Michael Birchall dismissing all the top three and finishing with 3-16 from four overs.
Leyland were then restricted to 90-9 after a shocking start which saw their top six total 15 between them. Jamie Thomson took most of those early wickets to finish 4-5 from his four overs.
Blackpool's top-order fared no better in the afternoon against Chorley, the first five scoring a combined 14 before Alex Ryder's 25 advanced them to 64-8, Sam Steeple taking 3-5 from four overs.
Chorley then sealed victory in 12.4 overs, reaching 65-2 with Roshen Silva unbeaten on 28 from 22 balls.
St Annes put up a fight away to Liverpool Competition club Ormskirk on Sunday in the preliminary round of the ECB National Knockout but bowed out by 35 runs.
The hosts were asked to bat and set an imposing 40-over target of 236-8 after openers George Politis (76) and Alex Rankin (56) put on 130. Mitch Bolus took 3-75 from eight overs.
St Annes' new professional Yohan De Silva then provided an exciting glimpse of his talents with 76 from 90 balls (with four fours and three sixes) as the visitors reached 201-6 in reply.
The Sri Lankan shared a fourth-wicket stand of 65 with Andy Drake (39) and Ormskirk's Harvey Rankin took 3-30.