I need advice!!!

Long weekend is coming up, and I am contemplating doing the 3-day potty training thing. My son is 2 years 5 months old. However, he doesn't seem to be really ready. Please help me decide if it would be a waste of time or if I should give it a try:

Ready signs:
- He could pull his pants / training diaper up and down, IF he wants to
- He peed and pooped in the potty many times over the past half a year. So he knows what it is for
- He does notify us when pee and poo is coming

Not Ready / Tricky signs:
- He never really wakes up with a dry diaper
- He always poop (and announce he's pooping) when he is eating a meal, making it difficult to take him to the bathroom (he wouldn't hold for it)
- Dirty diaper NEVER BOTHERS HIM. ARGH!!
- Recently he regressed, and I haven't really seen him pee in the potty. He also poop in the diaper without telling me.
- When he "announces" he needs to go, and I ask him if he wants to go to the potty, he would say NO 99.5% of the time.
- He definitely doesn't want to go to the potty when he's doing something, such as playing. It will be a meltdown if I make him go.
- Nothing really motivates him to use the potty: stickers or food. He likes it, but it just doesn't seem like he cares for it, or understand the "cause/effect"
- My fault: I still haven't bought underwear for him.
- Over the past half a year, he asked to go to potty, and successfully went, maybe 1-2 times. He normally NEVER asks to use the potty no matter how many times I explain to him he should.

I don't know. What are your thoughts?

Is it my fault that he is still not ready? Should I just force him to go on the potty even though he says no?

Do you think I should just give it a few more weeks/months? If you think it is OK to give him a crash course over the weekend, do you have any tips for me for a success?

Or really, any tips to help him become more ready would be highly appreciated!

ETA: I have 3 mommy friends and all of us have same age tots (birthdays only within 1+ week apart). The 2 girls are basically potty-trained (would ask to go to bathroom, motivated by candy...etc), and the boy (we go to the same daycare) has shown a lot more ready signs than LO. He recently moved onto the next class, ie. the potty training class, while we are still in the same class. I don't know, should I worry?