Tandy has only been able to select captain Jac Morgan in one fixture after the Lions flanker suffered a dislocated shoulder when scoring against Argentina in the autumn opener.
The Gloucester-bound Ospreys forward should return for summer fixtures against Fiji, Argentina and South Africa in the Nations Championship.
Wales have fielded Mann, influential number eight Aaron Wainwright, Botham, Olly Cracknell, Taine Plumtree, Josh Macleod and Harri Deaves in the Six Nations.
The legendary Faletau, Ryan Woodman, Tommy Reffell, Christ Tshiunza, Kane James, Ross Moriarty and Basham are among a glut of other options, with Deian Gwynne also shining in the Under-20s Six Nations.
Boss Tandy, a former flanker himself, has plenty to ponder.
Lydiate was part of a legendary back-row trio with Sam Warburton and Faletau that was joined by another stellar talent in Justin Tipuric.
“It’s connection. I knew what the other guys would deliver, so it’s about fitting the pieces of the puzzle together,” said Lydiate.
“When you have that synergy, what number is on your back doesn’t matter because you know what the other guys will give. You try and complement each other.
“We have gone through a bit of a transition and are figuring out who the best combinations are. We are probably still on that journey.”
Versatile Mann will make his fifth Test start of the season at blind-side – where he has exclusively started at Cardiff in 2025-26 – but is comfortable at open-side.
“He is a very good rugby player and you know what he will deliver no matter the number on his back,” said Lydiate.
“We’ve got Jac to come back into the fold, who is world class. The boys at the moment are setting the standards that others have to go higher than if they are to wrestle the jerseys off them.”
After a strong campaign, Mann will hope to sign off with a first Six Nations win.