Final update: Made my way through Victory Road, the most boring part of every game. Then beat Barry very easily due to having ridiculously over-levelled, beat Aaron with no problem, beat Bertha was slightly difficult and Flint and Lucian were easy as heck. Cythia was also very easily, but I made the mistake of assuming Pachirisu's Grass Knot could kill Gastrodon and Pachirisu fainted ;o; After beating Cynthia, did all the storyline stuff up until being able to do what I want again, caught a new Pachirisu wanted to hug the life out of it ;o; Levelled it up a bit in Victory Road with EXP share but then realised there was no point, went over to the Lost Tower and beat the rest of the trainers, got the final item (hidden stardust) and caught the remaining Pokemon there (Zubat, Ghastly and eventually came across a Golbat). Then headed over to the Old Chateau, went through at got all the items (including the 2 hidden ones), inserted LG and after A LOT of searching, caught a Lv 16 Haunter & finally a Gengar. Went upstairs caught the delightfully cute lil' Rotom <3 and am now... FINISHED! <3
Final Team
Drifblim - Level 62
Piplup - Level 58
Pachirisu - Level 37 (3 deaths, died against Cynthia D:)
Honchkrow - Level 59
Sandslash - Level 59
Toxicroak - Level 59