Midfielder Piazon helped Fulham earn promotion to the Premier League last season while centre-back Hector spent the 2017-18 campaign with Hull City having previously enjoyed spells at Eintracht Frankfurt and Reading.
Wednesday are looking to bolster their squad late in the transfer window having been placed under a transfer embargo for much of the summer - a ruling that has been cited as a key reason behind their slow start to the Championship campaign.
The Owls have won just one of their opening four matches - a 2-1 victory over Millwall on Tuesday - as they look to improve on their disappointing 15th-placed finish last term.
Meanwhile, Chelsea winger Charly Musonda has held discussions with a variety of clubs regarding a loan move having returned early from his agreed two-year spell at Celtic.
Ike Ugbo, meanwhile, is in advanced talks with League One outfit Scunthorpe United having spent last season on loan at Barnsley.
Scunthorpe sacked manager Nick Daws on Friday following their disappointing start to the season, with ex-Leeds United boss Paul Heckingbottom - who signed striker Ugbo for Barnsley last summer - one of the favourites to take over.
Fellow youngsters Izzy Brown, Islam Feruz and Fankaty Dabo are among those who are also actively looking to seal temporary moves away from Stamford Bridge before the Football League loan window closes on August 31 - the same day as it ends in many overseas countries.
Danny Drinkwater is the most senior member of Maurizio Sarri's squad to attempt to find a move elsewhere, but his large wages and the loan fee Chelsea are asking for has put off many potential suitors.
Either way, Chelsea's "loan army" could yet grow to in excess of 40 for the first time before the end of the month, with 32 players already having secured loan deals across the globe.
There is a will to reduce this number in the years to come, though, with the club instead aiming to use buy-back clauses in permanent deals to encourage more sales.