the only thing i would worry about is maybe your speaker in extreme cases, and your hearing. use a volume pedal after it to tame the louder frequencies that can occur when experimenting, or build a volume pot into the effect itself.

honestly don’t know the answer to that, and i build and sell different models of feedback loopers.

the buffer is a good hypothesis.

delays and modulation work well (phase, flang, chorus)
drive pedals are hit and miss, although if you cant get a modulation pedal to do anything, sum times it just needs a kick with a fuzz or distortion.

envelope filters are hit and miss as well, but there really cool when they do work.

if you have a couple dollars and want to experiment, i suggest buying a cheap multi effect pedal.

i use the Zoom MS-50G (only $99. new or cheaper used) you can use that to experiment with everything in one pedal, and if you like sum thing you can go buy a dedicated pedal of that effect type.

the Zoom is also a good backup in case anything your using breaks down at a gig, or you want to try/experiment with an effect type before buying one, that’s why i got one, i usually hate them but it was a good cheap emergency backup.

Ive been designing, building repairing, pedals, pedalboards, guitars, and small amps for aout 20 years but just locally for myself, friends, and local shops.

Ive only been selling stuff online for about 10 years, i build more advanced stuff on request, but the vids are really old (they all look and work way better now, i need to update) and that’s for the simple stuff i build in bulk and list for sale.

i still keep a day job, its only a hobby i enjoy for me in my spare time, the profit goes to my other hobbies like other guitar gear, horror films, and my children.

there’s always sum thing new to learn. i do research everyday out of enjoyment!