I think that firstly you need to ignore that well-meaning mother of yours. I'm sure things were done differently in her day, and you turned out just fine, blah, blah, blah, but this is your life and your baby and if you are choosing to follow the BW methods, it's your choice. What she's telling you to do is CIO which is not a method of sleep training that is endorsed by the BW community. Your LO is crying because that is the only way he knows to communicate with you. If you ignore that, you are not teaching him to self soothe, you are teaching him that his efforts at communication are in vain. It is impossible to spoil a baby at this age. He doesn't have the capacity to manipulate you, he's only communicating his needs with you and as his Mommy, it's up to you to sort it all out for him. It sounds like you are doing well with all of that, and you'll find that while the routine can be tough to establish and maintain, it's worth it for so many reasons.
I think your feeding routine looks great. At his age, most LOs can handle about 75 minutes of A time, including diaper change and feed. Do you know what temperament he is? Some LOs prefer/require a longer wind-down, some just a very short swaddle and into bed. If he starts to lose patience and get fussy during the wind-down, cut it shorter. My DD2 can tolerate being swaddled and turning the blinds with me and that is it. DD1 liked 3 lullabies and a cuddle, so they're all different.
Regarding his naps, IMO, it's best if they occur in the same place he sleeps at night. I find it helps reinforce the message that it is sleep time. Pat/shh is a wonderful method that is appropriate for his age and it will help him learn to self-soothe. He should be put down in his crib when he is calm but awake, and pat/shh is continued there until he stops crying. Then leave the room (or hang back out of his line of sight). If he starts up again and it's not a mantra cry (Mantra cry is not escalating, not an 'I need you' cry), go back to him immediately and pat/shh in the crib. It can take some time, so don't give up. The first few times it can take 30 minutes or so. If you do it for 40 minutes and he's still crying, get him up, feed and then try it again. The key really with any sleep training method is to be consistent. Consistent with the whole routine, the place he sleeps, wind-down, pat/shh, etc. If he doesn't nap for long, then the next A time should be shorter to make up for it so he doesn't get OT. Look for his cues, when he gets tired he may yawn, get fussy, look away from you, get 'glassy-eyed'... when you see those signs start the wind-down right away.
Check out the link here:
https://babywhispererforums.com/index.php?board=86.0, there's some great information about mantra cries, teaching sleep to newborns, wind-down routines...
Most importantly, try not to obsess about the 'schedule'. It's meant to be a flexible routine that helps your baby know what's coming next and helps you be able to plan your day accordingly. I know it's hard because you want to get it all 'right' but lots of babies don't fit the cookie cutter ideal of nap length or A time... it's all about knowing your baby, reading his cues, respecting his individuality and responding to what he needs.
HTH!
And hopefully others will come on to help address the many points in your post!