Garces, from France, will manage proceedings for the Friday night (19th) meeting with the Fijians, which kicks-off at the home of Welsh rugby at 17.15hrs, and South African Kaplan is chief moderator for the series crescendo clash with the All Blacks on Saturday 27th November (1700hrs).
The appointments were made by the IRB Match Official Selection Committee at its meeting in Dublin last weekend after a comprehensive review of international referee, assistant referee and television match official performances during the June internationals and recent Tri Nations.
The IRB International Referee Panel sees Walsh referee his first Tier One match since February 2008 when Wales play host to the Springboks at the Millennium Stadium on 13 November.
Ireland's Alain Rolland will kick off the busy Autumn period of matches as New Zealand take on Australia in the fourth Bledisloe Cup match in Hong Kong on 30 October, just a week before the Wallabies are in Cardiff.
"It is good to see Steve Walsh return to the International Referee Panel, while we are delighted to welcome Francisco Pastrana to the Assistant Referee Panel, having performed so well at the IRB Junior World Championship in Argentina this year," said IRB Referee Manager Paddy O'Brien.
"Both have impressed the selectors and deserve their reward, and Pastrana's selection reinforces the continued role of the development pathway created via the IRB Age Grade Championships and Sevens World Series in preparing referees for the Test arena."