Hadden plans to take 24 players on the two Test tour to South Africa, while Bates will have a 28-strong playing party for the three games in Canada.
The Warriors players are:
Backs: Colin Gregor, Andrew Henderson, Rory Lamont, Graeme Morrison, Dan Parks and Sam Pinder.
Forwards: Craig Hamilton, Scott Lawson, Donnie Macfadyen, Euan Murray, Jon Petrie, Fergus Thomson and Andrew Wilson.
Hadden said that players outwith the current 54 – which will train from May 15-17 – could yet feature on either tour.
Hadden and Bates have refrained from including any members of the Scotland under-21 squad in their squad at this stage given that the under-21s are preparing for the IRB World Championship in France in June.
Scotland/Scotland A joint squad for training at Murrayfield on May 15-17
Backs – Mike Blair (Edinburgh Gunners)*, Simon Danielli (Border Reivers), Matt Dey (Edinburgh Gunners), Nick De Luca (Edinburgh Gunners), Marcus Di Rollo (Edinburgh Gunners), Phil Godman (Edinburgh Gunners), Colin Gregor (Glasgow Warriors)*, Andrew Henderson (Glasgow Warriors), Duncan Hodge (Edinburgh Gunners), Rory Lamont (Glasgow Warriors), Sean Lamont (Northampton Saints), Rory Lawson (Edinburgh Gunners), Ben MacDougall (Border Reivers), Calum MacRae (Border Reivers)*, Brendan McKerchar (Border Reivers), Graeme Morrison (Glasgow Warriors), Dan Parks (Glasgow Warriors), Chris Paterson (Edinburgh Gunners), Sam Pinder (Glasgow Warriors), Gordon Ross (Leeds Tykes), Hugo Southwell (Edinburgh Gunners), Nikki Walker (Border Reivers), Simon Webster (Edinburgh Gunners)
Forwards – Ross Beattie (Northampton Saints), Kelly Brown (Border Reivers)*, Dave Callam (Edinburgh Gunners)*, Alasdair Dickinson (Edinburgh Gunners)*, Bruce Douglas (Border Reivers), Jon Dunbar (Leeds Tykes), Scott Gray (Border Reivers), Andy Hall (Newport Gwent Dragons), Dougie Hall (Edinburgh Gunners), Craig Hamilton (Glasgow Warriors), Nathan Hines (Perpignan), Allister Hogg (Edinburgh Gunners)*, Allan Jacobsen (Edinburgh Gunners), Alastair Kellock (Edinburgh Gunners)*, Andrew Kelly (Edinburgh Gunners)*, Gavin Kerr (Leeds Tykes), Scott Lawson (Glasgow Warriors)*, Nick Lloyd (Saracens), Donnie Macfadyen (Glasgow Warriors), Scott MacLeod (Border Reivers), Andy Miller (Border Reivers), Euan Murray (Glasgow Warriors), Scott Murray (Edinburgh Gunners), Jon Petrie (Glasgow Warriors), Mark Rennie (Lyon), Craig Smith (Edinburgh Gunners), Alasdair Strokosch (Edinburgh Gunners)*, Simon Taylor (Edinburgh Gunners), Fergus Thomson (Glasgow Warriors)* Jason White (Sale Sharks), Andrew Wilson (Glasgow Warriors)*
* = Member of Scottish Institute of Sport
Not considered due to injury: Graeme Beveridge (Glasgow Warriors), Simon Cross (Edinburgh Gunners), Chris Cusiter and Ross Ford (both Border Reivers), Robbie Kydd (Northampton Saints).