George Lazarov, usually transcribed as Georgi Lazarov (Георги Лазаров) in Stardust in ~1988, possibly his younger daughter, 9 yo Lazarina (Лазарина) and her granny Maria (Мария Лазарова-Меце) who both published their first book in Sept 2024. More info and source below.
I first tried to search for the Bulgarian film company Interfilm (of Sofia Press). In English there's almost nothing to find. Searching in cyrillic, I found a history mainly on one blog. And that's a real thriller. I don't know if it's all true and I don't want to tell about it. Bulgaria was communist then and 1 year later there were the big changes.
Rudi/Radoslav Dobrev was probably the only of the 5 kids with a big career. Searching in cyrillic, I only found Elena Atanasova (Елена Атанасова) being a stage actress. Costume staff lady Zweta Marinova also made a movie with Beppo Cino (In viaggio verso est, 1992).
Searching for George Lazarov was difficult. There's a tennis player, a stage player and then I found a blogger. With grey hair, I think he's too old. Searching for an actor, I found the lady above whose son is an actor and director.
She was a famous puppeteer in Plovdiv and in 2000-2008 she had a kids TV series Gotsometsania (Гоцомецания) together with her son on channel Eurocom Bulgaria, later E-Kids (see upcoming post).
She now published a book "The worms from the country Fruitstania and Mr. Parsley" (Червейчетата от страната Плодострания и господин Магданоз) illustrated by her granddaughter. Some characters in bibs. First link also showing an older girl
https://bnr.bg/plovdiv/post/102047844
https://gustomedia.bg/articles/mariya-lazarova-metse-predstavya-purvata-si-kniga-za-detsa-pred-plovdivska-publika-24-09-2024
https://plovdivdaily.bg/vnuchkata-na-mecze-narisuva-chervejchetata-ot-plodostraniya/
George might have played in 1985 Fantasy movie "Yan Bibiyan" (Ян бибиян целия филм бг аудио) but not as main character. And with costume probably not to recognize. In the 2024 indie, no-dialogue Western "Bo Nan Za" (БО НАН ЗА) he might have played as non pro and I think not showing in the trailer.