Winger Joe Cuff, goalkeeper Jono Brown and full-back Tyler Lyttle all featured in Tuesday's 4-0 victory at Market Drayton Town.
Two mystery men were also involved, after several others had been training with the Bucks.
"I'm meeting with the chairman to have a discussion on a few of them," said Cowan.
"It's football so some of them will fall by the wayside unfortunately – a few of them fell away before Tuesday night.
"Listen, we don't keep them around just for our own benefit.
"We make sure they're here if we're interested, and we're interested at this moment in time.
"I need to sit down with the chairman and look at what we might be able to do, and what we might not be able to do."
Cuff has been given an opportunity to impress after a stellar season at Drayton, being named players’ player of the year.
Brown was recently let go by National League North rivals Kidderminster Harriers, having had loan spells at Rushall Olympic and Sutton Coldfield Town over the past couple of years.
Lyttle, the son of former Nottingham Forest and West Brom star Des Lyttle, ended last season at Sutton Coldfield.
He was on the books of Bristol Rovers a couple of years ago and went to Thomas Telford.
Cuff got the most time on the pitch of the on-trial players at Greenfields, replacing Darryl Knights after half an hour and seeing out the game.
Brown replaced Sheridan Martinez between the sticks on the hour mark, while Lyttle started and was taken off in the second period. The other two trialists were a right-back and a left-back.
"They've got aspirations to play higher, and that's what they're doing here," added Cowan.
"We're giving them a platform to impress and if they do that, there might be an opportunity for them.
"If they don't, there won't be. Watch this space I suppose."
Jack Rea and Matthew Barnes-Homer, who started last season with Telford, have also been training and featured in friendlies.
Cowan 'wouldn't call them trialists', insisting he has been helping the pair boost their fitness as they search for clubs.