Yes, in terms of "economy," you may find it extra difficult to get a set of pieces like this performed. The whole set only takes up a minute and a half of concert time, but they require eight players. The more players you require, the harder it is to get on a program and the more substantial a piece has to be to earn a space in a concert.
Think like the director putting a concert together. Every time you need to add one more player, life becomes harder. Someone needs to know a good player who plays the instrument. That player needs to have a gap in their schedule that will allow them to make at least one rehearsal and the concert. If they are a professional player, you need to have funds to pay them. If they are not a professional, you need to be sure that they really can handle the music without stage fright issues.
So if a piece calls for 8 players, instead of 4, there needs to be an obvious reason that each player is really necessary. Because for each player you add, putting on the concert becomes slightly more difficult.
The groups I perform with both regularly change the instrumentation of pieces they perform. Either we can't manage to book a good quality harpist, so we cover the harp part on piano; or we can't justify hiring an English horn just for one piece in a 90-minute program, so we have someone else in the brass who isn't playing during those measures cover that English horn part. Sometimes there is no good work around solution, so we just decide not to add a piece to the program. Sometimes the composer, or a later editor, has thought about this possibility and there are several editions of the piece available, each with different numbers and varieties of instruments to cover all possible budgets and shortages of quality players.
Particularly because your "Sententia" are so short, they become harder to justify in a program. They aren't substantial enough to be half of a concert program, or a quarter of a program in which they are contrasted with other pieces in other styles. It's very rare for a director to be putting together a program and think, "I just need a minute more music." They need 10 minutes more. Or 15 minutes more. If you need a minute more music, you can just as easily do without the minute more music. It doesn't really solve a problem for the person deciding what will go into the program. Grouping these is a VERY good idea to get around that problem, but you may want to group them in larger numbers.
So if you want to write very short pieces, they are probably best for an instrument or two, as you have been doing, so they can be used in a recital setting. When a single player, or a player plus accompanist can pick whatever they want to play, it's easy for them to pick up one more piece, (your piece), to learn, just because they like it. The more people there are, the more expensive it becomes to add each piece, in terms of time and money, so there has to be enough content there to justify the choice of the piece. I think that's what Luis and Monarcheon are getting at.