No shame at all in having basic questions whether starting out or even 10 years in, always better to ask than do it wrong and cause damage
First thing is to decide if you want hifi listening or PA grunt work speakers. No speaker, no matter how well designed can do both. PA speakers are very much max SPL even at the cost of sound quality at times with higher levels of harmonic distorion accepted as OK. This typically results in them not sounding particularly pleasant for hifi listening, compression drivers tend to be very agressive sounding up close.
Second to that I would suggest not attempting active PA speakers if you are not experienced building your own speakers. When your pushing the wattages needed to play loud enough for a crowd the voltage and current handling of the electronics need to be more robust than small bookshelf speakers. You cant really do this both cheaply and safely!
I would suggest building fully passive speakers powered with an affordable PA amp and if you want a mobile solution you can use a small portable generator to power the amp. Im not the right person to recommend a specific amplifier to power these
Loudness – I would say you are more than good enough for 100 people with 800W 15inch woofers, ive done plays in 150 seat studio theatre with a pair of 300W 12inch woofer speakers.
I would ignore soundboks as a comparison as they are doing unique and propriatory things to achieve their numbers, I would say they are a completely different category of speaker all together. I understand they are using highly efficient calss D amplification and some form of amplifier switching and dynamic power management to further imporve efficiency. This will have needed serious ammounts of R&D and is even beyond something I would attempt to replicate at this time
Power – as stated above im not the right person to suggest an amplifier in this price category but others on here are alot more informed on this