Not at all - dont feel pressured into getting smaller plecs as most plecs are not predatory - the only thing to kind of mention is since you have so many open water fish you will need a fair amount of open space in the tank so the plecs might not be that visable unless you make specific shady areas for them.
hmmm what plecs would I do in here - mainly the really colourful ones, I think you need a spotty one at least, maybe a blue phantom.....
I think these would be my short list
http

/www.planetcatfish.com/catelog/species.php?species_id=308
http

/www.planetcatfish.com/catelog/species.php?species_id=204
http

/www.planetcatfish.com/catelog/species.php?species_id=213
http

/www.planetcatfish.com/catelog/species.php?species_id=210
http

/www.planetcatfish.com/catelog/species.php?species_id=126
http

/www.planetcatfish.com/catelog/species.php?species_id=635
http

/www.planetcatfish.com/catelog/species.php?species_id=229
I think my favorite 3 would be the L135, L187a and the L128 - L135 are a really nice plec I had one for a while and he was quite active but when I first got my fluval FX5 the pipes had bits missing and he got sucked in

Ive been seeing a lot of really good quality L187a around and they all look awesome their big mouths are so comical - and Blue Phantoms I want because they are becoming rare due to import ban and for that reason could shoot up in price and value soon but I dont know how much of a gamble that would be as it could be money you simply never see again?
Wills