It's not logic to play two WCL matches at once. The calendar of WCL distributed well aiming not to overload teams with many matches at the same time
@Bland_Joe seemed that you missed the main idea of WCL and ECL tournament. Hopefully 2 monthes get back you to the logic conclusion
As Kyiv did not accept our legal challenge 3 times in this tournament, we claim the 3 ponts due to the rules. Only "in case of a mutual decesion" can postpone a match. If we don' t get the points, Budapest won't play in this tournament, which works on the basis of sentences instead of the exact rules. These are our very last words about this topic, and maybe in this tournament as well. Bye!
Same thing in Moscow match vs Gdansk. They have only 6 players.
https://www.chess.com/club/matches/team-moscow/774764
When it will become possible to cancel that match?
Still waiting for Paris > https://www.chess.com/groups/team_match?id=775662 (14-11 in registration)
also,
Generally there is no problem with waiting for a few days, but now our small group in situation that has to play 2 regular rounds in two days + play against Paris if they get 12th player (a week after the scheduled date) and Quebec if they finally accept challenge (2 weeks after the scheduled date). Would it be possible to cancel at least Quebec challenge with default victory?
Acctually, all 3 scheduled matches of R4 are still waiting for begining!! Gdansk against Moscow and both Bordeaux and Thessaloniki don't have enough registered players yet, too.
And there is no info about 2 remaining R4 matches, Athens vs Bristol and Yerevan vs Beograd (probably will be also played as double match per WCL schedule?)
So, maybe some additional effort and/or making a few unpopular decisions is needed in order to have this competition to continue to work properly!? 
Athens should be awarded a default victory for R3 because Gdansk has rejected their challenge without public explanation (teams do not play in the same WCL division so it couldn't even be assumed that there was a wish for double match by WCL schedule, as a potential reason for challenge rejection)
It was also reported here that Thessaloniki has sent the challenge to Yerevan for R2 match, so they should also be awarded default victory since there is obviously no ongoing match between those two teams so it can be assumed that challenge is not accepted!?
However, there is still no explanation from either team was is going on with R2 match Bristol vs Gdansk ??
It is time now for R5 challenges (start on April 29-30) >
R5 - Budapest vs Moscow Athens vs Grad Nis Thesaloniki vs Beograd
Bordeaux vs Kyiv Bristol vs Yerevan Gdansk vs Paris
Notes >
Gdansk and Paris are in the same WCL division, already playing match https://www.chess.com/groups/team_match?id=745130, but with less players than ECL minimum for Div1! Important note may also be the fact that Paris player from this match kenthompson is currently listed as disqualified multiplayer for ECL, and also, of course, the fact that neither team has reported here that WCL match will be counted as double, as soon as this topic is created (since it was not possible at the time when match was created)
| ECL2017 R5: Grad Niš vs. Athens | 12+ | Open | 3 days | View |
https://www.chess.com/club/matches/774764
Gdansk has only 6 players. I claim victory by forfeit. Please, confirm.
- The minimum number of players required per match in order to be valid is:
for Division 1: 15 players (WCL), 12 players (ECL)
for Division 2: 12 players (WCL), 10 players (ECL)
for Division 3: 7 players (WCL), 6 players (ECL)
for Division 4: 5 players (WCL)
- In case that a match starts with less players for one or both teams, the opposing team needs to report a screenshot of a match dated from before of the start in order to receive extra board points for the missing games (ex. if 2 players are missing from team A, team B starts with +4 points). In order to start a match with less players each team would just “lock” their players and then the match could be started.
Do we HAVE to play?
Grad Niš - City of Nis 
Team Paris 
Team Athens
Team Beograd 
Well, I just wanted to explain how it works in practice. The very same way as WL+EL national teams matches.
The fact is that in WCL rules you can not see anything about playing double matches, right? (https://www.chess.com/groups/forumview/world-cities-league-rules-july-2015)
Playing double match with WCL one is only an option for ECL tournament, according to it's rules (https://www.chess.com/groups/forumview/ecl-rules-2016?page=1) "If two teams play in the same division for both WCL and ECL they should play double match except those cases when both teams agreed to play separate matches.", so the only logical conlcusion from all this is that double WCL+ECL match should be played by WCL schedule. Of course, if you agree with opponents, you can arrange an earlier start, but you can not forse anyone to agree to play double match by ECL schedule.