I would have thought your ds has an extremely positive outlook if he only has mild low tone and no issues with muscle strength. A cognitively bright child can LEARN how to do things other children can do instinctively, through teaching and practice. It's the attention, concentration, short term memory, social and perceptual issues often associated with dyspraxia that in the long run are the greater disability, so if he doesn't really show signs of having great difficulties in these areas, that's great. 2 years and 9 months is still incredibly young. At your son's current progress, if you keep him very active and help him with climbing playground equipment, going up and down stairs, trampolining, pedalling tricycles, going up and down kerbs, walking on uneven ground, swimming, etc, etc, you will see him, gradually, getting stronger and more stable.
My ds1 has hypotonia and hypermobility, and has had to be taught how to do a lot of physical things. At 2 and 9 months he was extremely unsteady on his feet and hugely behind his peers physically (and with speech - but that rapidly caught up after the age of 3, as in his case this was just a result of the low tone/normal late development, not a long-term inability to work out how to co-ordinate his mouth muscles). He's now 5 and can run, jump, climb, skip and hop (the latter still rather hard work for him), he can climb and descend stairs on alternating feet, can pedal a bike (may be a couple more years of practice before he can do this fast enough to try without stabilisers, but nevertheless, he CAN pedal, albeit slowly!) and can walk along a narrow balance beam. He will NEVER be any good at sport, but he will be able to keep fit and enjoy himself. He is also extremely happy at school, as now he is getting older, he can excel at the less physical things in life, like reading, writing (again, his hand tiring out may be an issue, but he can actually write surprisingly well for a hypermobile 5-year old), maths and using your imagination!