Given what our current system does and allows, there is... well something of a way you can do what you are suggesting, though it would be expensive, it'd definitely be something that could be built towards and make for an interesting theme with a navi. Object summons, if you make a navi with the summoner subtype you get a bonus to them. As for making the clones themselves, well that's where it gets a little tricky. To mimic the effects you are wanting though, there are steps that can be used.
The first would be the hp sacrifice nerf, this damages(in 15HP sets), but increases how many points you can use in a signature, then using objects, you could create a body double of the navi, it wouldn't have high hp until later levels, but you could also give it a passive movement, and a passive attack.
In this way, you could create an object that looks like the navi, and gets 1 movement and 1 attack each turn, which can more or less give the feel of what you are wanting. Naturally as you gain levels, you could increase the summon's power, it's costly, but doable.
Another option is to use a decoy summon, and in the signature include an attack, there is no rule that says attacks must always originate from the navi, so you can fluff it to originate from the decoy easily enough and it'd be allowed. Like above you could use the sacrifice nerf to give more points towards the signature.
The drawback to the first one, is of course the cost, it'd be highly expensive per object, that said, there really is no limit to how many you could make, as objects stay on the field until destroyed or the battle ends. So you could in theory build an army of them if the battle lasts a long time.
The drawback of the second is that decoys have a limit of staying in play for a single turn(unless you pay more to give it longer duration), so while it's the overall cheaper option, it's limited to how many turns you want it active, likewise decoys are destroyed by a single hit, since they effectively have an hp of 1.
Well, hope that at least answers your question on the idea, pretty clever. If you feel like it, hit us up on our discord and can freely talk about the ideas there, as pretty much everyone that's active is on there when not posting here. So you'll find the most active members in the chatroom there.
Welcome to the forum though, hope you enjoy yourself.