It depends on various things in your game, among other:
Are there bonuses that are temporarily and/or are lost when dying ?
How defended is the home-world itself ?

personally i would go with B & C, just like in LoL, have a safe spot nearby where players can retreat as well, maybe chat about their new battleplan and possibly send out a few long-range attacks.
(note that in LoL dying gives more penalties then just time, it also gives the other team gold and some XP, so even when respawn time is still low a safe place to retreat is still of high value)

The timing, in LoL at least, assures that eventually a team will win, this is for a big part because of the balance of LoL is very good(even between uneven teams) but i can imagine that if they make a new map that s balanced differently, they ll largely get rid of this. (they actually have an arcade-map called dominion which shows this iirc)

tl,dr; your question is not just about mechanic, but about balance, and that realy depends on the rest of your game.

The LoL mechanic of giving the enemy points could work quite will with a space ship game. The victor could take an enemy ship in tow, and rebuild what's left. Maybe even fight over the remains of ships as a resource.

Maybe they could count as some sort of research bonus towards tech onboard the destroyed ship.

Maybe some of the parts on the ship could be scavanged on the spot, stored as cargo, and carried back to a shipyard for incorporation in the next wave.

I'm liking this starship MOBA idea, good luck with it!

That's a good idea, for something simple to start off with i would specialize every ship-design on one tech (weapons, shields, engine, a few others) then destroying/harvesting an enemy ship that specializes in for example engines would give a bonus to your engines, though not at much as the original ship had as bonus(story: ships are build around their "best" tech and boost it with their design, but you can just put their engine in your ship and still have a part of the bonus; you don't give the full bonus because you do not want a player to gather a lot of bonuses and still give them all full, but maybe the first few taken bonuses could give more than 50% of their original bonus)

... for example engines would give a bonus to your engines, though not at much as the original ship had as bonus(story: ships are build around their "best" tech and boost it with their design, but you can just put their engine in your ship and still have a part of the bonus; you don't give the full bonus because you do not want a player to gather a lot of bonuses and still give them all full, but maybe the first few taken bonuses could give more than 50% of their original bonus)

The above idea of limiting the player's rewards can be counterproductive. I believe this resolves into communicating a sense of powerlessness or uselessness to the player, and that it will cause the project to lean more toward a simulation, with the player as one ant in a colony. Have you played some of those? They aren't a lot of fun.

Piracy is all about avoiding construction costs and overhead, and simply taking by force the finished product. "Gathering lots of bonuses" is a something the player wants, and is working to get. So as Stevie Nicks once sang, Give the players what they want. Don't be stingy or poor about it, be generous and fill their cup to overflowing; give them a great time.

Hmm, in the suggestion i made giving bonuses at full when taking it during the game would unbalance the game, unless the bonuses itself(and everyone would start with one bonus) would be rather low.
Plus giving full bonus for whatever a player chooses makes different ships, well, different(specialization)