I often make bass-sized baits (4" or less). I haven't done any lipped muskie/pike baits yet, so if that's your aim I can't vouch for this technique. I also haven't put the line-tie in a lip yet, always in the lure body.
I often just use superglue. I've used a variety of brands and have had pretty good success. I haven't had any problems with lips coming out or loosening up. I've taken a few lips out of baits, and they always take wood with them and basically bust things up. One way I've done it is to use thick super glue (even the gel stuff) and fill the lip slot as described above and then inserted the lip, wiping off the excess. Alternatively, I've used thin super glue after inserting the lip. The glue is so thin it penetrates and seeps into any gaps.
This technique comes with a disclaimer. While I have watched many of Marling Bait's videos on YT and seen him do it many times, I've only made maybe 30 baits like this, so I don't have near the experience over time as some others here.