You can sew lycra and spandex by hand if you do not have a sewing machine.
The trick is to stretch while you sew. How do you do this? Simple.
Get a stabilizer. They can be found at most chain craft stores. Or! use freezer paper, found at every grocery store. Iron the stabilizer onto the fabric (wax side down if it's freezer paper), and zig-zag stitch by hand. Then tear off the stabilizer (it's really easy to remove), fold the stitch over, and straight stitch for extra security.
Zig-Zag/Overcast by hand: https://sew4home.com/tips-resources/...s-tricks/hand-
I'd recommend against the fabric glue for spandex/lycra. The point of the fabric is to be able to stretch as it moves. The glue doesn't do that as well and can cause things to fall off.
As dbchan suggested, you can use velcro (sew the velcro onto the suit, attach the velcro to the accessories).