More advantageous? Again, it depends where and with what you are starting out with. First you said you have a partially built plane , now it's a plane with 3 engines. What else do you have ?
If you have all of the glow engine support equipment like a starter, field box, glowstick, tools, etc..those are things you won't have to buy as opposed to buying electric batteries, a good charger, and a 40 size electric motor and speed control.
A 2-stroke glow engine requires some experience to properly tune it and keep it tuned in different flying conditions. It's not overly difficult and it becomes second-nature after you have done it for awhile.
Your best bet is to find a local club and/or someone who has flown glow engine planes and have them look at your engines and they will tell you if they can be used or not.