I'm not certain if there is a way to affect capsaicin levels in a given plant , others may know if at all possible.

It would indeed be better to wait for the plant to get larger, enabling it to support a larger crop of peppers, so pinching-off buds is probably a good idea for now. They'll come back en masse on the grown plants.

You would have to go for the mild variety TAM mild (does have some heat) or the no heat "Fooled You" jalapeno. Jalapeno plants grow fast and the few early peppers you took off should be fine.

Core the pepper, and scrape the white ribs out. It will tame the heat of even the hottest of the jalapenos.

New Mex Big Jim or Anaheim are milder than the Jalapeno pepper. Take a look at this scoville scale for pepper varieties

http://pepperheadsforlife.com/the-scoville-scale/

Concur with the above comments. Variety is the major factor. TAM mild has low heat. There are a number of varieties which have Jalapno flavor but no heat, Fooled You, False Alarm, Felicity, Coolapeno etc.