Ah glad you got a later WU it really does help make things feel better if you can catch up on a bit of sleep.
I think if you are using cc to tackle the feeds at night then yes it would be best to use it for naps too, so you are being entirely consistent, otherwise he will still need your help. And wouldn't it be lovely to have him napping in the cot - I tell you I LOVE my LO's naptime - 2hrs of me time every day!
If your LO really won't take a second nap, then there are 2 things I would certainly recommend you try:
Firstly, I would suggest an early bedtime of about 6pm (or even 5.30pm if you dare!) whilst he's still napping at 10am ish. You may think this is crazy but if you bear in mid he is often awake by 10.45am/11.30am latest, he is going between 7-8 hours before his usual BT, after a relatively short nap.
Often people think that the only way to get LO's to sleep later in the morning is with a later bedtime, but in fact this can cause them to wake earlier if they are overtired at bedtime. Particularly during this transition, until his nap is at around lunchtime, you may find that it really helps. And even if he still gets up at 5am, he will have had an hour's more sleep IYSWIM?
Secondly, I would try to work on very gradually shifting his nap later in the morning, towards lunchtime. So put him down at 10am for a week or 2, then 10.15am for a week or 2, then 10.30am & so on. If 15min increments are too much for him you could always push it later by 5mins every 3-5 days. As the nap shifts a little later he will start to nap for longer (when on 1 nap & esp at this young age you ideally want a nap of 2hrs+). As the nap gets gradually later you can shift his bedtime back towards 7pm & eventually he will take his nap at around lunchtime.
This is a gradual process & may take some time, & you may encounter some overtiredness along the way but trust me this will help (exactly what we did to tackle EW & we now have 7am WU's!)
HTH.x