On the verge of appointing a new senior coach, the last-placed Bombers will be out to avoid the wooden spoon when they host Port Adelaide at Marvel Stadium on Sunday.
The match is a dead rubber, with the Power also out of finals contention.
McGrath will lead Essendon in his milestone appearance amid uncertainty over six-time club best-and-fairest winner Merrett's playing future.
Merrett was denied his wish to break his contract and join arch-rivals Hawthorn in last year's trade period, and there is speculation he will again demand a move when the current campaign ends.
But Solomon said Merrett had been an "incredible" support for him as interim coach and a "powerful" leader of an inexperienced playing group throughout the season.
The 46-year-old interim boss, whose own future at Essendon is also still to be decided once a new coach is appointed, was also full of praise this week for McGrath.
The 28-year-old took on the senior leadership role when Merrett stepped down after his failed bid to join the Hawks.
"Andy's a beautiful human and he's carried so much this year - so much responsibility within the four walls of our football club," Solomon said.
"He's been incredible with the support he's given so many players and staff through what has been a difficult (season), and he's led in an elite manner.
"I can't speak highly enough of Andy and it's critically important that we carry him off (the ground) and put him in the centre of that circle and sing the song."
Solomon urged fans to turn up and show support for the Bombers in their season-ending fixture after another poor crowd witnessed last Sunday's loss to Sydney.
Only 24,767 fans were on hand to make up Essendon's lowest MCG attendance for 33 years, outside of the COVID-19 pandemic.
"It's a really disappointing position that we're in as a club and the crowds are low as a result, but I totally understand it and we all understand it," Solomon said.
"But also, glass half-full, there is a young group starting to form in front of their eyes that are really quite exciting.
"I just encourage our members and supporters, although it's been a difficult time, to also see the positives that are starting to shine through."
Essendon have lost their last four matches by an average margin of 67 points, while Port have suffered six consecutive defeats, including thrashings from Melbourne (76 points) and Sydney (97 points) over the past fortnight.
Power star Zak Butters fell short in his attempt to return for an ankle injury for what could have been a possible farewell appearance against the Bombers.
The dual All-Australian is a restricted free agent and weighing offers from Victorian clubs, with the Western Bulldogs and Geelong widely thought to be leading the chase.
Port coach Josh Carr said the final-round affair would be largely business as usual for his side, albeit with an eye towards next season.
"There's so much we can work on within our game," Carr said.
"The great part about having so many younger players in the team is they get a real-life experience of AFL football and trying to transfer our training into our games.
"It's a great opportunity with one game to go to finish strong and get back to playing with some real method.
"To finish off with a win would be nice but it's not the be-all and end-all for us. There's a bigger picture that we've got to think of."
