Short answer to your questions is a pretty flat NO.
If each device truly is an LRU, it needs to be individually powered. Sometimes this is simply so you can take one LRU off line for troubleshooting purposes while leaving others powered. Sometimes you need to power them up one at a time for software updates.
With respect to your question around ganging devices on a 2amp breaker, think of it this way. On Saturday you hop in your Cessna Caravan with one kid. Mid-flight that kid says he is hungry for a granola bar and you happen to have ONE granola bar in the airplane. You feed the kid, the kid is happy as he had an appetite for one granola bar.
Now it's Sunday and you have SIX kids in your Caravan. You've wisely re-stocked the galley with your one trusty granola bar. Mid-flight you have SIX kids, each with a one-granola-bar hunger yelling they're hungry. You have one granola bar. Exactly how many kids are going to be happy if you split that granola bar six ways? ZERO kids will be happy.
Same goes for LRU's.
Now for a MUCH BIGGER CONCEPT...
Circuit protection devices (breakers, fuses) protect the circuit. DOH! Sounds pretty obvious, doesn't it? Well, the CIRCUIT is the WIRE!!! It's NOT the LRU!!! If an LRU has a specific need for power input protection, that protection will be located INSIDE the LRU.
Spend some time with AC43.13 and get familiar with its wire sizing and circuit protection charts. Fuse or breaker the wires based on the WIRE SIZE. Avionics manufacturer's recommendations for circuit protection sizes are a guideline based on the power consumption of their device, NOT on airworthiness requirements of the total installed system including the long-term continuing airworthiness requirements of the aircraft. Take their recommendation for wire size, double-check it against 43.13 and choose the bigger of the two wires (manufacturer wire size will take into account things like inrush current, while 43.13 takes into account things like whether the wire is in a conduit or a bundle).
I know this sounds like I'm being a bit of a jerk, but the reality is that if we stick with this basic concept of fusing the wire to protect the wire and its ability to conduct current, we are future-proofing ourselves. Imagine Garmin or Dynon had a little box with only a few functions that consumed one amp and was fed by a 20ga wire (by their recommendation). A couple of years later they come out with a replacement device that does a zillion different things, has a far brighter display, a far faster processor, and takes 4 amps. If you installed a 1A circuit breaker you're going to be kicking yourself. If, however, you installed the 7.5A breaker that 43.13 would have recommended, you have no problems in changing the LRU to the new fancy box without ever having to worry about how well its power input wiring is protected.
See, when you look at it that way, protecting the wire based on the wire's needs makes a whole lot of sense. That's why it's the industry standard method for electrical system design!