Looking from what his routine looks like now, I think he may be UT for the morning nap, but after this short nap the following A even though on a shorter side for his age r causing him OT, which in turn gets worse as the day wears on and r also causing the NWs.
But at least now his routine is looking a lot more like what he should be doing at his age.
Heres what I would do:
1. Increase his As. Start with the first A of the day. At the moment it is 2.5h, typical A for his age is2.75-3h. Increase this A by 10-15m. Keep in mind that increasing A might not show any results for a few days, and always work on one A at a time.
2. Even with increased A he still might need some help extending this nap, here u could do pu/pd or shh/pat or w2s.
3. Once he takes a nice long nap, u can start working on the next A of the day. Again increase A and work on helping him to get through to the next sleep cycle.
4. U can also go into him jus before the 30m wake up mark and be there as he stirs and help him transition to the next cycle by either applying preasure (if it is jolts that r causing him to wake up) or just soothing with shh/pat or words r whatever helps him sleep.
5. It might actually be a good idea to just go into him on one of his naps and be there as he wakes up, just watch him and see what it is that is causing him to wake up, this might provide some usefull insights into what u can do to help him sleep longer.
6. If u notice him getting OT through out the day aim for an earlier bedtime, don't be afraid to put him down as early as 1 hour before his bedtime. An earlier bedtime wil be more beneficial than a short CN in the evening.
7. Also if he is up early from his nap, the time u spent trying to get him back to sleep should be included in his next A, and the next nap should be moved accordingly. With consistent short naps through out the day u may need to have his bedtime way early which is ok as this should allow him to sleep better during the night.
Hang in there! U r making progress even though at the moment it may not seem like it but u have made some serious improvments. This may take a while but trust ur hard work will pay off!!!
{{{Big Hugs}}} Nothing worse than sleepless nights.
Hope this helps