Hello and welcome to BW forums

Sounds like you are doing brilliantly with your second LO in getting to know him so well so quickly and working out his eat and sleep needs, plus caring for two LOs so young. amazing

A few things I can come back on with regards to your information and routine etc.
First, I am not all that familiar with baby wise however I believe it follows a similar pattern of eat, activity, sleep.
I must make it clear from the off though that Tracy Hogg, the Baby Whisperer methods and and members of this community do not support any form of controlled crying at all. My understanding of baby wise is that some form of CC is used for sleep training which is in opposition with the Baby Whisperer ethos and will not be supported on this forum.
It looks anyway like you have chosen a gentler, respectful approach with your LO2 and we can certainly support you with that. I would suggest you get yourself a copy of the Baby Whisperer book and familiarise yourself with the sleep training approach, or there are lots of FAQs on this forum that you can read through (if you have time!).
Activity time.
I've seen general EASY sample schedules for this age showing 1.5 hours of wake time
I'm not sure which board or thread you saw this on. For an 8 wk old baby the guidance time is not as long as 1hr 30, it is 1hr 15 to 1hr 20. Here are the guidance times by age:
https://babywhispererforums.com/index.php?topic=84884.0However, we do emphasise that these are for guidance only and not every baby is expected to fit in these times rigidly. Every EASY routine is different based on the individual needs of your LO. Yes we might start with those guidance times when setting up a routine for a LO who has previously had no routine, but we would then adapt the routine when we see how LO responds.
In your case, you have already implemented a routine and worked out a suitable A time for your LO because you know he does well on shorter that guidance A times, roughly 60 mins (max) and then naps well.
Also your LO arrived a little early so this would always be taken into consideration when looking at routine and development etc. You do not need to be concerned for routine purposes about whether LO was 34 or 37 wks but rather just keep in mind during this first year that your LO's routine might be that of a slightly younger baby. Just now then your LO is having A times which are following the guidance time of his adjusted age, newborn to 4wks old, 50 - 60 min guidance A time which kind of fits with that assessment of 34/35 wks and with your own observations of him starting to wake up to the world.
As he is still so tiny and as you have a toddler to care for too, I would probably suggest that you continue with your moby wrap naps for now as they seem to be going well for you and allowing LO2 to sleep well whilst also fitting in with the family needs. Independent sleeping is something you can tackle when you feel ready to and perhaps when he is a little older - it is not something you have to do right now. It is helpful to sleep train because ultimately your LO is going to grow big and heavy and it will be very hard work to keep sling naps going every single day for every nap. You will likely feel more ready to do a little sleep training when his A times are longer too - just now the short A time doesn't give you a chance to get out or get back home in time for a nap but in time the A with extend and then you may see a suitable spot in your routine where sleep training can begin. For instance if your toddler takes an afternoon nap which is reliable you might use that time to focus on LO2 to begin cot naps and gentle sleep training at that time of day, whilst keeping the other naps in sling or stroller. It's also possible to do some sleep training in the stroller (either at home or out and about) which would give you a bit more flexibility whilst he is so young - yes it's not exactly independent sleep but it might be more practical for you.
I hope this helps. Please do feel welcome to look around at the FAQS and to ask any questions you have either here or on other boards.