No, it doesn't break any guidelines or rules for a matter like this, back to topic
There are two methods to obtain Gen 1 pokemon in Gen 7 games, the first one is using PokeBank, which is the official method of transferring Pokemon from older generations to new ones, given that you're asking in the homebrew 3DS section, you are probably looking for a free method to do so, right? if so then, the second method may be for you
The second method consists of backing up the save data from your VC games (or from any R/B/Y rom) for then to open them with the use of PkHex, the program will immediately recognize the save data as a Gen 1 game and the recent updates gave it the option to transfer those Pokemon into Sun and Moon
To transfer those pokes, you need as stated before to open the saves from that Gen 1 game, and then you pick a Pokemon that you want (a pikachu, a charmander, whatever) available in your battle box or PC's and then you export them as a pk1 file on your PC, later on you will open a save from your Sun and Moon games (forgot to mention, you need to backup your SuMo savedata with either savefilemanager or jksm) once in there, add the pk1 file while the SuMo savefile is open, and guala! that's about it, it may be a tedious process since you can't transport boxes, but you can backup this Pokemon and have them in both games so you won't ever lose any poke at all.
I heard of things about PKSM but I don't know if it has compatibility for that, check up the current state of that program in doubt
The program has evolved a lot since then, it has compatibility for every main Pokemon game, and now it has features such as legality checker and QR generator, it is very easy to use and tutorials are available everywhere