Yes on both accounts.
My calculations:
Via Liverpool
[Table 82] Orrell - Kirkby: 8.5 miles
[Table 103] Kirkby - Moorfields: 7 miles
[Table 106] Moorfields - Lime Street Low Level: 0.5 mile
[Table 90] Lime Street High Level - Wavertree: 2.5 miles
Total: 18.5 miles (This is also the shortest route wholly by rail.)
The distance in the opposite direction via Liverpool Central is 0.5 mile longer.
Via Wigan
[Table 82] Orrell - Wigan Wallgate: 3.75 miles
[Table 90] Wigan North Western - Wavertree via St Helens Central: 17.5 miles
Total: 21.25 miles (This is no more than 3 miles longer than the shortest route, therefore also permitted. No negative easements apply.)