imo you can totally get into raids and fractals with 2-3 people.

For fractals, you're just 2 shy of a full party. Throw a post up on LFG and it'll be filled in 5 minutes easy.

For raids, have your friends learn healers or supports and you'll quickly fill the remaining spots with "hi dps"-ers. Or honestly just having a 3/10 LFG post up will get some gamers filled in regardless of what you play. In my experience it's the 1/10 groups that are the slowest to get started. Just make sure you post for the right roles ("w1 full clear lf adps,qdps" for example) so people know what the group needs.