Trimble's return sees Craig Gilroy shift to the left wing and Stefan Terblanche revert to full-back, with Adam D'Arcy the player to make way.
Ian Whitten and Darren Cave again form the centre partnership, while Ruan Pienaar and Ian Humphreys continue as the starting half-backs.
Best and Court are included in the front row in place of Andi Kyriacou and the injured Paddy McAllister. They are joined by All Black prop John Afoa, who picked up the man-of-the-match award in the 33-17 win over Munster last weekend.
Captain Johann Muller and Dan Tuohy once again combine in the second row. Ferris' inclusion at blindside flanker results in Chris Henry moving to the openside berth, while Pedrie Wannenburg remains at number 8.
Paddy Wallace has returned to the squad after seven weeks on the sidelines with tendon damage in his thumb.
With Ulster just seven points adrift of fourth spot in the RaboDirect PRO12, a win would be a huge boost to their hopes of progressing to the play-offs, but defeat would be damaging.
This is a point not lost on McLaughlin. He said: "It's a crucial game for us, not only in terms of the PRO12, but also with Europe in mind next week.
"Edinburgh have been playing well this season and like to play a good brand of rugby, but we will be looking to put in a quality performance and getting the result."
The Ulster boss is pleased to be welcoming back some senior players, adding: "Training has been excellent all week. It's been great having the internationals back, including Paddy (Wallace).
"It really gives us a boost coming into such important games and they will bring a bit extra to the team tomorrow night. They're itching to get involved again and we are looking forward to having them back in."
McLaughlin also admitted that he was faced with some tough decisions in terms of selection this week.
"Adam D'Arcy has been playing very well over the past few matches but Stefan has a bit more experience and we wanted to give him an opportunity to impress at full-back.
"With Andrew coming back in it gave us an opportunity to rotate a bit and make use of the strong squad we've assembled."
ULSTER (v Edinburgh): Stefan Terblanche; Andrew Trimble, Darren Cave, Ian Whitten, Craig Gilroy; Ian Humphreys, Ruan Pienaar; Tom Court, Rory Best, John Afoa, Johann Muller (capt), Dan Tuohy, Stephen Ferris, Chris Henry, Pedrie Wannenburg.
Replacements: Andi Kyriacou, Callum Black, Adam Macklin, Lewis Stevenson, Willie Faloon, Paul Marshall, Paddy Wallace, Adam D'Arcy.