Negotiations were set to resume on Tuesday morning, with Wednesday night's trade deadline looming large.
There was widespread speculation on Monday afternoon that the Houston deal was going ahead.
Houston, the two-time All-Australian defender, would have been at the centre of the deal after he requested a trade to a Melbourne club.
Gold Coast's No.13 draft pick, which had reached near-mythical status in trade speculation over the past few days, would also go to Port as part of the deal.
Suns player Jack Lukosius would have his wish granted and head to Port. Rory Atkins would also leave Gold Coast for Alberton and Collingwood defender John Noble would go to the Suns.
Joe Richards was the fifth player in the proposed deal, going from Collingwood to Port Adelaide. Other current and future draft picks were also to change hands between the three clubs.
Fremantle are keen if Liam Baker's preferred trade from Richmond to West Coast falls through. (Joel Carrett/AAP PHOTOS)
The trade period started a week ago and the only real progress before Monday had been Friday's stunning deal, with Hawthorn sending their No.14 draft pick to Carlton.
That complicated the negotiations over Houston and also made it a lot harder for West Coast to secure a deal for Richmond's Liam Baker.
Houston, Baker and Lukosius are among several players whose futures remain unclear as trade negotiations continue.
Meanwhile, Fremantle are making a big pitch to the Tigers and Baker, should the Eagles negotiations fall through.
Baker wants to reunite with new Eagles coach Andrew McQualter, with the pair having worked together at Richmond.
The scenario before Friday had been that the No.14 selection would be used as part of the Hawks bringing in defender Tom Barrass from the Eagles, who then would pass on that pick in the Baker deal.
"Our understanding is his desire is still to get to West Coast," Dockers football manager Joe Brierty told AFL Trade Radio on Monday morning.
"We're respectful of that ... (but) he suits our list and our profile, and if the opportunity was to arise, we feel we have the collateral to meet Richmond's needs.
"Ultimately, it's in Liam's corner. We'll continue to have those discussions with (him) and his manager."
Fremantle's main trade target is another Richmond player, Shai Bolton, while teammate Daniel Rioli wants to reunite with former Tigers coach Damien Hardwick at the Suns.
Also on Monday morning, Essendon and Melbourne completed a swap of draft picks that sent the Bombers' No.9 selection to the Demons.
It means Melbourne have the fifth and ninth picks in what is considered a strong draft, while Essendon can recruit their highly rated academy prospect Isaac Kako.
Melbourne and Adelaide swapped draft picks to open Monday's trade action before the Demons-Bombers pick swaps were confirmed.
As part of the deal, Melbourne sent six lower 2024 and 2025 draft picks to Essendon.
Bailey Smith and Jake Stringer are among other key names in the trade mix.
The Western Bulldogs and Geelong continue to haggle over Smith, who wants to leave the kennel and head to the Cats. Stringer could go from Essendon to GWS.
In other AFL news, star Carlton defender Jacob Weitering signed a six-year contract extension.
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