Shopify eCommerce Store Customization

Our store ([login to view URL]) is on Shopify Platform. We desire some help in doing certain customization. We have the online presence and Shopify's POS presence. Below are brief high level on each customization needed. 1. POS model - we use iPAD with Shopiy POS app and Shopify card reader. When a customer charges for some service, we would like to interface with an cheap signature pad that capture customer's signature and post it in the order instead of customer signing in the iPad 2. We want make the amount a variable. In other words suggest an minimum and customers/ devotees can override and enter mount over to the minimum set. At the moment we are using a 3rd party app called "Pay What You Want". It work only for online version and not on POS - looking for solution that works for both online and POS 3. Have monthly subscription capability. We are using a 3rd party app "Recharge - Recurring Billing & Subscriptions". The feature works only on online store - Need the feature to work on both online and POS with the similar capability 4. Like to run customized customer/ devotee report attach an intro and with Temple officer signature at the bottom, make the report a PDF and give secure access to such report when customer logs into their account 5. Backend UI capability or POS entry capability to change/ enter custom service/ payment date of identified orders 6. Within POS operation, Shopify only has ACH payments option as plain vanilla. No ability to capture actual ACH info and interface with bank/ payment process.