One may use many types of gums as Gelatine Replacer in gummy bears - Pectin HM and LM , Modified Agar , Refined kappa Carragenan , Konjac etc and also thin boiling modified starches as Roy sir suggested.
Easiest to use would be starches but the downside is that it would be a bit hazy from outside and inside but the upside is that starch has a taste synergy with juices and the taste of gummy bears will be very clean and offcourse the easiest and safest process .
HM pectin in this application is known to have textural issues ,and all the more difficult for u as u intend to use acidity of fruits for gelation, which may make ur operation prone to batch variations and constant changes in formulation.
LM pectin is very difficult to use and requires constant small changes in formulation from batch to batch depending on raw materials and typical water requirements …batch to batch variation is a distinct possibility specially in small operations.
Agar agar typically requires good practice and expertise , specially for small manufacturers for fear of acid hydrolysis of agar agar ( and consequent loss of viscosity) if timing is not kept precisely .
The best bet , in my opinion is to use refined kappa carageenan . It gives rise to clear and glassy looking product , has clean mouthfeel and is the cheapest of all gums and starches. The process time is much lower , the role of buffers is not much important ( though not absent )…and the risk of batch failing is very very low( as also with starches , most safe)…